Yocto-spi : user's guide

Yocto-SPI : User's guide

1. Introduction
1.1 Prerequisites
1.2 Optional accessories
2. Presentation
2.1 Common elements
2.2 Specific elements
3. First steps
3.1 Localization
3.2 Test of the module
3.3 Configuration
4. Assembly and connections
4.1 Fixing
4.2 USB power distribution
5. The SPI port
5.1 Configurable parameters
5.2 Frame-based binary protocol
5.3 Protocol based on text lines
5.4 Binary data stream
5.5 ASCII data stream
6. Automatic measures
6.1 Communication jobs
6.2 Tasks
6.3 Commands
6.4 The genericSensor functions
6.5 Configuration example
7. Programming, general concepts
7.1 Programming paradigm
7.2 The Yocto-SPI module
7.3 Module control interface
7.4 SerialPort function interface
7.5 External power supply control interface
7.6 GenericSensor function interface
7.7 DataLogger function interface
7.8 Files function interface
7.9 What interface: Native, DLL or Service ?
7.10 Programming, where to start?
8. Using the Yocto-SPI in command line
8.1 Installing
8.2 Use: general description
8.3 Control of the SpiPort function
8.4 Control of the module part
8.5 Limitations
9. Using Yocto-SPI with EcmaScript / JavaScript
9.1 Blocking I/O versus Asynchronous I/O in JavaScript
9.2 Using Yoctopuce library for EcmaScript
9.3 Control of the SpiPort function
9.4 Control of the module part
9.5 Error handling
10. Using Yocto-SPI with PHP
10.1 Getting ready
10.2 Control of the SpiPort function
10.3 Control of the module part
10.4 HTTP callback API and NAT filters
10.5 Error handling
11. Using Yocto-SPI with C++
11.1 Control of the SpiPort function
11.2 Control of the module part
11.3 Error handling
11.4 Integration variants for the C++ Yoctopuce library
12. Using Yocto-SPI with Objective-C
12.1 Control of the SpiPort function
12.2 Control of the module part
12.3 Error handling
13. Using Yocto-SPI with Visual Basic .NET
13.1 Installation
13.2 Using the Yoctopuce API in a Visual Basic project
13.3 Control of the SpiPort function
13.4 Control of the module part
13.5 Error handling
14. Using Yocto-SPI with C#
14.1 Installation
14.2 Using the Yoctopuce API in a Visual C# project
14.3 Control of the SpiPort function
14.4 Control of the module part
14.5 Error handling
15. Using Yocto-SPI with Delphi
15.1 Preparation
15.2 Control of the SpiPort function
15.3 Control of the module part
15.4 Error handling
16. Using the Yocto-SPI with Python
16.1 Source files
16.2 Dynamic library
16.3 Control of the SpiPort function
16.4 Control of the module part
16.5 Error handling
17. Using the Yocto-SPI with Java
17.1 Getting ready
17.2 Control of the SpiPort function
17.3 Control of the module part
17.4 Error handling
18. Using the Yocto-SPI with Android
18.1 Native access and VirtualHub
18.2 Getting ready
18.3 Compatibility
18.4 Activating the USB port under Android
18.5 Control of the SpiPort function
18.6 Control of the module part
18.7 Error handling
19. Advanced programming
19.1 Event programming
19.2 The data logger
19.3 Sensor calibration
20. Firmware Update
20.1 The VirtualHub or the YoctoHub
20.2 The command line library
20.3 The Android application Yocto-Firmware
20.4 Updating the firmware with the programming library
20.5 The "update" mode
21. Using with unsupported languages
21.1 Command line
21.2 VirtualHub and HTTP GET
21.3 Using dynamic libraries
21.4 Porting the high level library
22. High-level API Reference
22.1 General functions
22.2 Module control interface
22.3 SerialPort function interface
22.4 External power supply control interface
22.5 Files function interface
22.6 GenericSensor function interface
22.7 DataLogger function interface
22.8 Recorded data sequence
22.9 Measured value
23. Troubleshooting
23.1 Linux and USB
23.2 ARM Platforms: HF and EL
24. Characteristics
25. Index

1. Introduction

The Yocto-SPI is a 48x20mm USB module used to communicate with electronic devices using an SPI protocol at 3.3V or 5V CMOS/TTL levels. It also features a voltage output to power that device with 3.3V or 5V. The Yocto-SPI always has the master role (SPI Master). Its buffer memory enables it to communicate asynchronously, if need be. In the opposite to other USB/SPI adaptors, it does not need drivers and, most importantly, its use does not require any virtual COM port.

On top of offering a byte-for-byte SPI communication interface, the Yocto-SPI can autonomously question and analyze any appliance with a SPI interface to then present the results in the manner of a Yoctopuce sensor. In other words, the Yocto-SPI can transform any sensor equipped with a SPI interface into the software equivalent of a Yoctopuce sensor, data logger included.


The Yocto-SPI module

Yoctopuce thanks you for buying this Yocto-SPI and sincerely hopes that you will be satisfied with it. The Yoctopuce engineers have put a large amount of effort to ensure that your Yocto-SPI is easy to install anywhere and easy to drive from a maximum of programming languages. If you are nevertheless disappointed with this module, do not hesitate to contact Yoctopuce support1.

By design, all Yoctopuce modules are driven the same way. Therefore, user's guides for all the modules of the range are very similar. If you have already carefully read through the user's guide of another Yoctopuce module, you can jump directly to the description of the module functions.

1.1. Prerequisites

In order to use your Yocto-SPI module, you should have the following items at hand.

A computer

Yoctopuce modules are intended to be driven by a computer (or possibly an embedded microprocessor). You will write the control software yourself, according to your needs, using the information provided in this manual.

Yoctopuce provides software libraries to drive its modules for the following operating systems: Windows, Mac OS X, Linux, and Android. Yoctopuce modules do not require installing any specific system driver, as they leverage the standard HID driver2 provided with every operating system.

Windows versions currently supported are: Windows XP, Windows 2003, Windows Vista, Windows 7 and Windows 8.1. Both 32 bit and 64 bit versions are supported. Yoctopuce is frequently testing its modules on Windows XP and Windows 7.

Mac OS X versions currently supported are: 10.6 (Snow Leopard), Mac OS X 10.7 (Lion), 10.8 (Mountain Lion), and 10.9 (Maverick). Yoctopuce is frequently testing its modules on Mac OS X 10.9 and 10.7.

Linux kernels currently supported are the 2.6 branch and the 3.0 branch. Other versions of the Linux kernel, and even other UNIX variants, are very likely to work as well, as Linux support is implemented through the standard libusb API. Yoctopuce is frequently testing its modules on Linux kernel 2.6.

Android versions currently supported are: Android 3.1 and later. Moreover, it is necessary for the tablet or phone to support the Host USB mode. Yoctopuce is frequently testing its modules on Android 4.x on a Nexus 7 and a Samsung Galaxy S3 with the Java for Android library.

A USB cable, type A-micro B

USB connectors exist in three sizes: the "standard" size that you probably use to connect your printer, the very common mini size to connect small devices, and finally the micro size often used to connect mobile phones, as long as they do not exhibit an apple logo. All USB modules manufactured by Yoctopuce use micro size connectors.


The most common USB 2 connectors: A, B, Mini B, Micro A, Micro B.3

To connect your Yocto-SPI module to a computer, you need a USB cable of type A-micro B. The price of this cable may vary a lot depending on the source, look for it under the name USB A to micro B Data cable. Make sure not to buy a simple USB charging cable without data connectivity. The correct type of cable is available on the Yoctopuce shop.


You must plug in your Yocto-SPI module with a USB cable of type A - micro B.

If you insert a USB hub between the computer and the Yocto-SPI module, make sure to take into account the USB current limits. If you do not, be prepared to face unstable behaviors and unpredictable failures. You can find more details on this topic in the chapter about assembly and connections.

1.2. Optional accessories

The accessories below are not necessary to use the Yocto-SPI module but might be useful depending on your project. These are mostly common products that you can buy from your favorite hacking store. To save you the tedious job of looking for them, most of them are also available on the Yoctopuce shop.

Screws and spacers

In order to mount the Yocto-SPI module, you can put small screws in the 2.5mm assembly holes, with a screw head no larger than 4.5mm. The best way is to use threaded spacers, which you can then mount wherever you want. You can find more details on this topic in the chapter about assembly and connections.

Micro-USB hub

If you intend to put several Yoctopuce modules in a very small space, you can connect them directly to a micro-USB hub. Yoctopuce builds a USB hub particularly small for this purpose (down to 20mmx36mm), on which you can directly solder a USB cable instead of using a USB plug. For more details, see the micro-USB hub information sheet.

YoctoHub-Ethernet and YoctoHub-Wireless

You can add network connectivity to your Yocto-SPI, thanks to the YoctoHub-Ethernet and the YoctoHub-Wireless. The YoctoHub-Ethernet provides Ethernet connectivity and the YoctoHub-Wireless provides WiFi connectivity. Both can drive up to three devices and behave exactly like a regular computer running a VirtualHub.

Enclosures

Your Yocto-SPI has been designed to be installed as is in your project. Nevertheless, Yoctopuce sells enclosures specifically designed for Yoctopuce devices. These enclosures have removable mounting brackets and magnets allowing them to stick on ferromagnetic surfaces. More details are available on the Yoctopuce web site 4. The suggested enclosure model for your Yocto-SPI is the YoctoBox-Long-Thick-Black.


You can install your Yocto-SPI in an optional enclosure

2. Presentation


1:Micro-B USB connector6:SS (slave select)
2:Yocto-led 7:SCK (serial clock out)
3:Yocto-button 8:SDO (serial data out)
4:Transmit led 9:SDI (serial data in)
5:3.3V / 5V power output10:Ground

2.1. Common elements

All Yocto-modules share a number of common functionalities.

USB connector

Yoctopuce modules all come with a micro-B USB socket. The corresponding cables are not the most common, but the sockets are the smallest available.

Warning: the USB connector is simply soldered in surface and can be pulled out if the USB plug acts as a lever. In this case, if the tracks stayed in position, the connector can be soldered back with a good iron and using flux to avoid bridges. Alternatively, you can solder a USB cable directly in the 1.27mm-spaced holes near the connector.

Yocto-button

The Yocto-button has two functionalities. First, it can activate the Yocto-beacon mode (see below under Yocto-led). Second, if you plug in a Yocto-module while keeping this button pressed, you can then reprogram its firmware with a new version. Note that there is a simpler UI-based method to update the firmware, but this one works even in case of severely damaged firmware.

Yocto-led

Normally, the Yocto-led is used to indicate that the module is working smoothly. The Yocto-led then emits a low blue light which varies slowly, mimicking breathing. The Yocto-led stops breathing when the module is not communicating any more, as for instance when powered by a USB hub which is disconnected from any active computer.

When you press the Yocto-button, the Yocto-led switches to Yocto-beacon mode. It starts flashing faster with a stronger light, in order to facilitate the localization of a module when you have several identical ones. It is indeed possible to trigger off the Yocto-beacon by software, as it is possible to detect by software that a Yocto-beacon is on.

The Yocto-led has a third functionality, which is less pleasant: when the internal software which controls the module encounters a fatal error, the Yocto-led starts emitting an SOS in morse 5. If this happens, unplug and re-plug the module. If it happens again, check that the module contains the latest version of the firmware, and, if it is the case, contact Yoctopuce support6.

Current sensor

Each Yocto-module is able to measure its own current consumption on the USB bus. Current supply on a USB bus being quite critical, this functionality can be of great help. You can only view the current consumption of a module by software.

Serial number

Each Yocto-module has a unique serial number assigned to it at the factory. For Yocto-SPI modules, this number starts with YSPIMK01. The module can be software driven using this serial number. The serial number cannot be modified.

Logical name

The logical name is similar to the serial number: it is a supposedly unique character string which allows you to reference your module by software. However, in the opposite of the serial number, the logical name can be modified at will. The benefit is to enable you to build several copies of the same project without needing to modify the driving software. You only need to program the same logical name in each copy. Warning: the behavior of a project becomes unpredictable when it contains several modules with the same logical name and when the driving software tries to access one of these modules through its logical name. When leaving the factory, modules do not have an assigned logical name. It is yours to define.

2.2. Specific elements

The connector

The Yocto-SPI module contains a input/output SPI port following CMOS/TLL standards, which can be configured for 3.3V or 5V logical levels. The Yocto-SPI always works as SPI Master, which means the SCK line (serial clock) is always an output that must be connected to the clock input on the slave device. The SDO (serial data out) of the Yocto-SPI must be connected to the SDI line of the slave device, and the SDI (serial data in) of the Yocto-SPI must be connected to the SDO line of the slave device.

Activity leds

The Yocto-SPI has a green led indicating the activity of the SPI port. The led lights up each time the module triggers a SPI transmission. As any SPI transmission is implicitly the counterpart of a reception, there is no separate led to signal receptions.

3. First steps

When reading this chapter, your Yocto-SPI should be connected to your computer, which should have recognized it. It is time to make it work.

Go to the Yoctopuce web site and download the Virtual Hub software7. It is available for Windows, Linux, and Mac OS X. Normally, the Virtual Hub software serves as an abstraction layer for languages which cannot access the hardware layers of your computer. However, it also offers a succinct interface to configure your modules and to test their basic functions. You access this interface with a simple web browser8. Start the Virtual Hub software in a command line, open your preferred web browser and enter the URL http://127.0.0.1:4444. The list of the Yoctopuce modules connected to your computer is displayed.


Module list as displayed in your web bowser.

3.1. Localization

You can then physically localize each of the displayed modules by clicking on the beacon button. This puts the Yocto-led of the corresponding module in Yocto-beacon mode. It starts flashing, which allows you to easily localize it. The second effect is to display a little blue circle on the screen. You obtain the same behavior when pressing the Yocto-button of the module.

3.2. Test of the module

The first item to check is that your module is working well: click on the serial number corresponding to your module. This displays a window summarizing the properties of your Yocto-SPI.


Properties of the Yocto-SPI module.

This window allows you, among other things, to play with your module to check how it is working. You can find there a simplified terminal emulator enabling you to test the communications of your module.

3.3. Configuration

When, in the module list, you click on the configure button corresponding to your module, the configuration window is displayed.


Yocto-SPI module configuration.

Firmware

The module firmware can easily be updated with the help of the interface. To do so, you must beforehand have the adequate firmware on your local disk. Firmware destined for Yoctopuce modules are available as .byn files and can be downloaded from the Yoctopuce web site.

To update a firmware, simply click on the upgrade button on the configuration window and follow the instructions. If the update fails for one reason or another, unplug and re-plug the module and start the update process again. This solves the issue in most cases. If the module was unplugged while it was being reprogrammed, it does probably not work anymore and is not listed in the interface. However, it is always possible to reprogram the module correctly by using the Virtual Hub software 9 in command line 10.

Logical name of the module

The logical name is a name that you choose, which allows you to access your module, in the same way a file name allows you to access its content. A logical name has a maximum length of 19 characters. Authorized characters are A..Z, a..z, 0..9, _, and -. If you assign the same logical name to two modules connected to the same computer and you try to access one of them through this logical name, behavior is undetermined: you have no way of knowing which of the two modules answers.

Luminosity

This parameter allows you to act on the maximal intensity of the leds of the module. This enables you, if necessary, to make it a little more discreet, while limiting its power consumption. Note that this parameter acts on all the signposting leds of the module, including the Yocto-led. If you connect a module and no led turns on, it may mean that its luminosity was set to zero.

Logical names of functions

Each Yoctopuce module has a serial number and a logical name. In the same way, each function on each Yoctopuce module has a hardware name and a logical name, the latter can be freely chosen by the user. Using logical names for functions provides a greater flexibility when programming modules.

SPI port configuration

You can configure the workings of the SPI port in this window. You can select the speed, the SPI mode, the bit encoding, the voltage of the communication line, and the polarity of the SS line.

You can also select the protocol that you want to use on the SPI line. You can find more details about the different protocols in the chapter entitled 5. SPI port.

You can choose the voltage level used by the SPI port. The Yocto-SPI features 3 modes:

This setting is saved in the flash memory. Make sure to check the voltage twice before connecting a device to the Yocto-SPI, as a wrong setting is likely to damage the connected device. The Yocto-SPI is shipped with this setting set to OFF.

Power output configuration

Le Yocto-SPI features a power output allowing it to power the connected circuit with 3.3V or 5V. You can count on ~200mA when the chosen voltage is 3.3V and ~450mA when the chosen voltage is 5V.

This setting is also saved to the flash memory, make sure you check it twice before connecting a device to the Yocto-SPI. Using the wrong voltage might destroy your hardware. The Yocto-SPI is shipped with this setting set to OFF. When configuring both the SPI port level and the power output, make sure that voltage on the SPI port is never greater than the power supply. Therefore, it is preferable to turn on the power output, then power the SPI port, as most electronic devices don't like receiving a signal voltage on their input pins above their power supply.

4. Assembly and connections

This chapter provides important information regarding the use of the Yocto-SPI module in real-world situations. Make sure to read it carefully before going too far into your project if you want to avoid pitfalls.

4.1. Fixing

While developing your project, you can simply let the module hang at the end of its cable. Check only that it does not come in contact with any conducting material (such as your tools). When your project is almost at an end, you need to find a way for your modules to stop moving around.


Examples of assembly on supports

The Yocto-SPI module contains 2.5mm assembly holes. You can use these holes for screws. The screw head diameter must not be larger than 4.5mm or they will damage the module circuits. Make sure that the lower surface of the module is not in contact with the support. We recommend using spacers, but other methods are possible. Nothing prevents you from fixing the module with a glue gun; it will not be good-looking, but it will hold.

If your intend to screw your module directly against a conducting part, for example a metallic frame, insert an isolating layer in between. Otherwise you are bound to induce a short circuit: there are naked pads under your module. Simple packaging tape should be enough for electric insulation.

4.2. USB power distribution

Although USB means Universal Serial BUS, USB devices are not physically organized as a flat bus but as a tree, using point-to-point connections. This has consequences on power distribution: to make it simple, every USB port must supply power to all devices directly or indirectly connected to it. And USB puts some limits.

In theory, a USB port provides 100mA, and may provide up to 500mA if available and requested by the device. In the case of a hub without external power supply, 100mA are available for the hub itself, and the hub should distribute no more than 100mA to each of its ports. This is it, and this is not much. In particular, it means that in theory, it is not possible to connect USB devices through two cascaded hubs without external power supply. In order to cascade hubs, it is necessary to use self-powered USB hubs, that provide a full 500mA to each subport.

In practice, USB would not have been as successful if it was really so picky about power distribution. As it happens, most USB hub manufacturers have been doing savings by not implementing current limitation on ports: they simply connect the computer power supply to every port, and declare themselves as self-powered hub even when they are taking all their power from the USB bus (in order to prevent any power consumption check in the operating system). This looks a bit dirty, but given the fact that computer USB ports are usually well protected by a hardware current limitation around 2000mA, it actually works in every day life, and seldom makes hardware damage.

What you should remember: if you connect Yoctopuce modules through one, or more, USB hub without external power supply, you have no safe-guard and you depend entirely on your computer manufacturer attention to provide as much current as possible on the USB ports, and to detect overloads before they lead to problems or to hardware damages. When modules are not provided enough current, they may work erratically and create unpredictable bugs. If you want to prevent any risk, do not cascade hubs without external power supply, and do not connect peripherals requiring more than 100mA behind a bus-powered hub.

In order to help controlling and planning overall power consumption for your project, all Yoctopuce modules include a built-in current sensor that tells (with 5mA precision) the consumption of the module on the USB bus.

5. The SPI port

In the opposite to other SPI adapters, the Yocto-SPI SPI port is not a simple gateway to a virtual COM port. It is based on an active communication management by the module and offers a full programming interface like for all Yoctopuce modules. In particular,

Thanks to these functions, you can use the Yocto-SPI to, for example, perform SPI communications from a simple command line or from an HTTP request on a REST interface, without risking to lose messages.

The Yocto-SPI SPI port can talk to any SPI CMOS/TTL circuit in 3.3V or 5V. The usual four SPI modes, corresponding to polarity and the synchronization edge of the SCK clock line, are all supported. You can also configure the polarity of the SS line (slave select).

5.1. Configurable parameters

The Yocto-SPI SPI port can generate communication speeds from 31 Kbits/s to 4 Mbits/s. It supports the four usual SPI modes11:

Most SPI protocols transmit bytes with the Most Significant Bit first (msb first). In the rare case when a protocol uses the inverse convention, you can configure the Yocto-SPI to work in Least Significant Bit first (lsb first).

You can also configure the polarity of the SS line. The common usage is to lower the line when sending the message and to release it afterwards (active low), but you can also use the inverse convention.

You can also configure in the module the protocol family that is going to be used on the SPI port. This allows the module to pre-analyze the data directly when it receives them, and to optimize the information exchange with the applicative code, in particular to signal reception of new data when most convenient (that is when a complete message has been received). The distinct protocol families that are supported are detailed in the following sections.

5.2. Frame-based binary protocol

Called Frame-based binary protocol in the configuration interface, this family includes all proprietary protocols based on exchanging binary messages (non-textual). It is the most frequent case on SPI interfaces. The SS line is automatically activated right before sending the message, and released at the end of the message. You can specify a minimal interval to be respected between each message, depending on the needs of the slave device.

The most useful API functions in this working mode are:

In binary frame mode, if you register a value notification callback, it is called for each newly received frame.

5.3. Protocol based on text lines

Called Line-based ASCII protocol in the configuration interface, this protocol family is relatively seldom used on SPI ports, working traditionally in binary mode. It is however supported for analogy with serial communication ports.

The most useful API functions in this working mode are:

In line mode, if you record a value notification callback, it is called each time a new message is received.

5.4. Binary data stream

Called Generic byte stream in the configuration interface, it is the binary equivalent of the ASCII data stream. You access it as you would a binary file, with the possibility to move the read position pointer freely inside the 16KB read buffer. Note that the read position pointer is specific to each application: if two applications read access the SPI port through the network simultaneously, moving the read position pointer of one application does not have any impact on data availability for the other application.

When using this type of protocols, the SS line is not automatically driven. You must therefore drive it explicitly if need be.

The most useful API functions to to work with a binary data stream are:

In stream mode, if you register a value notification callback, it is called each time a byte is received.

5.5. ASCII data stream

Called Generic ASCII stream in the configuration interface, it is the most primitive text communication variant, similar to a file access. As the Yocto-SPI has a 16KB read buffer, it is even possible to move the read position pointer freely within this window. Note that the read position pointer is specific to each application: if two applications read access the SPI port through the network simultaneously, moving the read position pointer of one application does not have any impact on data availability for the other application.

When using this type of protocols, the SS line is not automatically driven. You must therefore drive it explicitly if need be.

The most useful API functions to to work with an ASCII data stream are:

In stream mode, if you register a value notification callback, it is called each time a byte is received.

6. Automatic measures

On top of offering the means to perform low level SPI communications, the Yocto-SPI can work at a superior abstraction level. It can autonomously question a device through the SPI port and present the values read as measures, in the same manner as all the Yoctopuce sensors. This includes the possibility to store the measures on the internal flash memory (data logger). Potentially, this enables you to transform any device equipped with a SPI port into a native Yoctopuce sensor, with all the advantages this brings in terms of ease for software integration.


The Yocto-SPI can automatically send and receive data on the SPI port.

6.1. Communication jobs

The Yocto-SPI contains a file system on which you can store jobs, which are in fact simple text file in the JSON format. A job describes write and read actions to be performed on the SPI port. In the VirtualHub interface, the window describing the Yocto-SPI properties allows you to select which job must be run, while the configuration window enables you to select which job must be run when the module starts. The Yocto-SPI runs only one job at a time, but a job can perform actions in parallel.

Job structure

A job is essentially a set of tasks which are independent from one another. Each task can send data on the SPI port and/or react to the arrival of data on the SPI port.

Job definition and management

You can define jobs with the VirtualHub, in the Yocto-SPI configuration window. Click on the manage files button and a window containing the list of defined jobs appears.


Job management window

This window enables you to select which job to run, to edit, or to delete. It also allows you to define a new job, either with the help of an interface or by directly uploading it on the module file system. To create a new job, click on define a new job. This opens the job creation window.


Job creation window

As a job is only a set of tasks, this window only allows you to give a name to the job and to manage the tasks it contains.

Creating a job by software

While there is no explicit API to define a job by software, a job is only a text file put in the file system of the Yocto-SPI. To configure the Yocto-SPI by software, you simply need to upload the correct file on the Yocto-SPI with the YFiles class and to program its running with the selectJob() or set_startupJob() functions of the YSpiPort class. The easiest way to create a job file without risking to make an error consists in using the VirtualHub to configure the desired job on a Yocto-SPI module, and then to download the corresponding file.

6.2. Tasks

Each task is a simple list of commands to run sequentially: sending data on the SPI port, waiting, reading data, and so on. There are two types of tasks: reactive tasks and periodic tasks.

Reactive tasks

A reactive task is triggered by the device connected to the Yocto-SPI: the task is automatically run as soon as data corresponding to predefined patterns appear on the port. Most often, a task simply consists in interpreting these data and in assigning them to one or several genericSensor functions available on the Yocto-SPI. Reactive tasks are particularly useful to interface devices that send a continuous flow of measures on their SPI port. If the module detects data with a pattern corresponding to two distinct tasks, both tasks are run in parallel.

The VirtualHub allows you to easily create a good number of reactive tasks, such as:

But you can also define personalized tasks by typing the task commands directly.


Reactive task creation interface

You can assign data that are read to any Yocto-SPI genericSensor functions. From the developer stand point, the device that is connected to the Yocto-SPI through its SPI port appears like any usual Yoctopuce sensor. All the normal Yoctopuce sensor features (callbacks, data logger, averaging, and so on) are then available without any additional effort.

Beware, the SPI protocol defined in the Yocto-SPI configuration must correspond to the needs of the job. For instant, you cannot detect binary frames if the Yocto-SPI is configured in line-based ASCII mode.

Periodic tasks

A periodic task is a task that is run at a regular interval, at the Yocto-SPI initiative. They are generally used to send commands to the device connected to the Yocto-SPI. Here again, the VirtualHub allows you to easily define a number of common tasks:

You can also define a task manually, one command after the other, or start by using a predefined task as above and edit it afterwards to add commands.

You can also assign data read in a periodic task to the Yocto-SPI genericSensor functions. Beware, the SPI protocol defined in the Yocto-SPI configuration must correspond to the needs of the job: for example, you cannot detect binary frames if the Yocto-SPI is configured in line-based ASCII mode.


Periodic task creation interface

Although periodic tasks are designed to be run at regular intervals, you can define a "periodic" task that is run only once. Periodic tasks are run in the order in which they are defined. You can therefore define a job containing a first non recurrent task to configure your device, and a second task, recurrent, to question it in a loop.

You can mix periodic and reactive tasks in a same job. You must however pay careful attention to their triggering events in order to prevent them from perturbing each other. The Yocto-SPI always waits until the end of a periodic task before running the next one. However, reactive tasks can be triggered at any time, even in parallel to a periodic task.

6.3. Commands

You can use the following commands in a (periodic or reactive) task:

WAIT

The wait command waits for a given number of milliseconds before running the following command.

LOG

The log command displays a character string in the logs of the Yocto-SPI.

WRITE

The write command sends a character string as is on the SPI line. The string is sent without additional carriage return.

WRITELINE

The writeLine command sends a character string on the SPI line, followed by a line break (CR-LF).

WRITEHEX

The writeHex command sends a binary message on the SPI line. The parameter is the hexadecimal representation of the message to be sent (lower and upper case are supported).

EXPECT

The expect command waits for the data corresponding to a given pattern to appear on the SPI line. If the module is configured in binary mode, the correspondence is established on a hexadecimal representation of the binary data.

The expect command takes a character string as argument. We support some regular expressions:

SETSS

The setSS command manually modifies the state of the SS line, if the proprietary protocol is not correctly managed by the automatic command function. To use this command, select a protocol of the Generic byte stream or Generic ASCII stream type to disable automatic management of the SS line.

SETPOWER

The setPower command automatically enables and disables the voltage applied to the sensor. With it, you can for example automatize the cold start of the sensor.

If, for a reason or another, a command generates an error, you can find the traces of this error in the logs of the Yocto-SPI.

6.4. The genericSensor functions

9 genericSensor functions are available in the Yocto-SPI. Jobs running on the module can freely assign them values. You can access these genericSensor functions from the Yoctopuce API with the YGenericSensor class. You can also configure these functions to tailor their behavior depending on the nature of the reported values.


genericSensor configuration window

Unit

You can define the measuring system in which the value stored by the genericSensor is specified.

Resolution

You can define the resolution in which the value reported by the genericSensor must be represented.

Mapping

You can automatically apply a linear transformation to the values stored in a genericSensor. Indeed, some devices do not directly provide a physical quantity on their SPI output. Let us imagine a voltmeter transmitting values between 0 and 65535 for measures between 0 and 10V. You can have the genericSensor function automatically perform an inverse conversion as illustrated below.


Linear conversion example.

This mechanism is also very useful for automatic conversions, for instance to convert feet into meters.

6.5. Configuration example

Here is a job example to interface a commercial sensor.

Alphasense OPC-N2 particulate sensor

The Alphasense OPC-N2 particulate sensor is an optical sensor able to measure the air quality in terms of PM1, PM2.5, and PM10 particulates. It requires a 5V power source and transmits its measures in SPI (mode1) in 3.3V levels. This sensors agrees to communicate at a relatively high speed, but is very sensitive about the minimal interval between sent bytes. A simple way to respect this interval is to communicate at 63 Kbit/s and to systematically force a 10ms pause between the first byte of the commands and the following ones.

Numerous SPI commands are available in the sensor, but only two are enough to obtain the most important pieces of information. To start, the following command allows you to turn on the laser and the fan in the sensor:

03 00

Then, the following command allows you to read the PM1, PM2.5, and PM10 measures. Each one of these measures is returned as a 32 bit floating point number, therefore 12 bytes to be received. You must therefore send the (32) command followed by 12 useless bytes (32 as well) which are used to receive the measures.

32 32 32 32 32 32 32 32 32 32 32 32 32

Step 1

Configure the Yocto-SPI to provide a 5V power source to the sensor and for a communication in "Frame-based binary protocol", 63Kb/s, SPI mode 1, msb first, with signals in TTL 3.3V, and an active SS line.


SPI port configuration for an Alphasense OPC-N2 sensor

Step 2

Create a job with two tasks: the first one, used to turn the sensor on, is sent only every 30 seconds. The second, used to read the measures, is sent every second. The first task is the simplest, you only need to respect the waiting requirements between the bytes that you send.


Task example to start an Alphasense OPC-N2 sensor

Reading the measures is similar but calls the EXPECT command to decode the measures and publish them in the genericSensor1 to genericSensor3 functions:


Task example to read an Alphasense OPC-N2 sensor

The complete character string that you must use with the EXPECT command is the following:

($1:FLOAT32)($2:FLOAT32)($3:FLOAT32)

Step 3

Run the job to check that it works by displaying the functions of each module in the VirtualHub main page. If the result is not what you expected, check the module logs.

7. Programming, general concepts

The Yoctopuce API was designed to be at the same time simple to use and sufficiently generic for the concepts used to be valid for all the modules in the Yoctopuce range, and this in all the available programming languages. Therefore, when you have understood how to drive your Yocto-SPI with your favorite programming language, learning to use another module, even with a different language, will most likely take you only a minimum of time.

7.1. Programming paradigm

The Yoctopuce API is object oriented. However, for simplicity's sake, only the basics of object programming were used. Even if you are not familiar with object programming, it is unlikely that this will be a hinderance for using Yoctopuce products. Note that you will never need to allocate or deallocate an object linked to the Yoctopuce API: it is automatically managed.

There is one class per Yoctopuce function type. The name of these classes always starts with a Y followed by the name of the function, for example YTemperature, YRelay, YPressure, etc.. There is also a YModule class, dedicated to managing the modules themselves, and finally there is the static YAPI class, that supervises the global workings of the API and manages low level communications.


Structure of the Yoctopuce API.

The YSensor class

Each Yoctopuce sensor function has its dedicated class: YTemperature to measure the temperature, YVoltage to measure a voltage, YRelay to drive a relay, etc. However there is a special class that can do more: YSensor.

The YSensor class is the parent class for all Yoctopuce sensors, and can provide access to any sensor, regardless of its type. It includes methods to access all common functions. This makes it easier to create applications that use many different sensors. Moreover, if you create an application based on YSensor, it will work with all Yoctopuce sensors, even those which do no yet exist.

Programmation

In the Yoctopuce API, priority was put on the ease of access to the module functions by offering the possibility to make abstractions of the modules implementing them. Therefore, it is quite possible to work with a set of functions without ever knowing exactly which module are hosting them at the hardware level. This tremendously simplifies programming projects with a large number of modules.

From the programming stand point, your Yocto-SPI is viewed as a module hosting a given number of functions. In the API, these functions are objects which can be found independently, in several ways.

Access to the functions of a module

Access by logical name

Each function can be assigned an arbitrary and persistent logical name: this logical name is stored in the flash memory of the module, even if this module is disconnected. An object corresponding to an Xxx function to which a logical name has been assigned can then be directly found with this logical name and the YXxx.FindXxx method. Note however that a logical name must be unique among all the connected modules.

Access by enumeration

You can enumerate all the functions of the same type on all the connected modules with the help of the classic enumeration functions FirstXxx and nextXxxx available for each YXxx class.

Access by hardware name

Each module function has a hardware name, assigned at the factory and which cannot be modified. The functions of a module can also be found directly with this hardware name and the YXxx.FindXxx function of the corresponding class.

Difference between Find and First

The YXxx.FindXxxx and YXxx.FirstXxxx methods do not work exactly the same way. If there is no available module, YXxx.FirstXxxx returns a null value. On the opposite, even if there is no corresponding module, YXxx.FindXxxx returns a valid object, which is not online but which could become so if the corresponding module is later connected.

Function handling

When the object corresponding to a function is found, its methods are available in a classic way. Note that most of these subfunctions require the module hosting the function to be connected in order to be handled. This is generally not guaranteed, as a USB module can be disconnected after the control software has started. The isOnline method, available in all the classes, is then very helpful.

Access to the modules

Even if it is perfectly possible to build a complete project while making a total abstraction of which function is hosted on which module, the modules themselves are also accessible from the API. In fact, they can be handled in a way quite similar to the functions. They are assigned a serial number at the factory which allows you to find the corresponding object with YModule.Find(). You can also assign arbitrary logical names to the modules to make finding them easier. Finally, the YModule class contains the YModule.FirstModule() and nextModule() enumeration methods allowing you to list the connected modules.

Functions/Module interaction

From the API standpoint, the modules and their functions are strongly uncorrelated by design. Nevertheless, the API provides the possibility to go from one to the other. Thus, the get_module() method, available for each function class, allows you to find the object corresponding to the module hosting this function. Inversely, the YModule class provides several methods allowing you to enumerate the functions available on a module.

7.2. The Yocto-SPI module

The Yocto-SPI is an autonomous SPI interface, with built-in datalogger.

module : Module

attributetypemodifiable ?
productName  String  read-only
serialNumber  String  read-only
logicalName  String  modifiable
productId  Hexadecimal number  read-only
productRelease  Hexadecimal number  read-only
firmwareRelease  String  read-only
persistentSettings  Enumerated  modifiable
luminosity  0..100%  modifiable
beacon  On/Off  modifiable
upTime  Time  read-only
usbCurrent  Used current (mA)  read-only
rebootCountdown  Integer  modifiable
userVar  Integer  modifiable

spiPort : SpiPort
attributetypemodifiable ?
logicalName  String  modifiable
advertisedValue  String  modifiable
rxCount  Integer  read-only
txCount  Integer  read-only
errCount  Integer  read-only
rxMsgCount  Integer  read-only
txMsgCount  Integer  read-only
lastMsg  String  read-only
currentJob  String  modifiable
startupJob  String  modifiable
command  String  modifiable
voltageLevel  Enumerated  modifiable
protocol  Type of messaging protocol  modifiable
spiMode  SPI parameters  modifiable
ssPolarity  Signal polarity  modifiable
shitftSampling  On/Off  modifiable

powerOutput : PowerOutput
attributetypemodifiable ?
logicalName  String  modifiable
advertisedValue  String  modifiable
voltage  Enumerated  modifiable

genericSensor1 : GenericSensor
genericSensor2 : GenericSensor
genericSensor3 : GenericSensor
genericSensor4 : GenericSensor
genericSensor5 : GenericSensor
genericSensor6 : GenericSensor
genericSensor7 : GenericSensor
genericSensor8 : GenericSensor
genericSensor9 : GenericSensor
attributetypemodifiable ?
logicalName  String  modifiable
advertisedValue  String  modifiable
unit  String  modifiable
currentValue  Fixed-point number  read-only
lowestValue  Fixed-point number  modifiable
highestValue  Fixed-point number  modifiable
currentRawValue  Fixed-point number  read-only
logFrequency  Frequency  modifiable
reportFrequency  Frequency  modifiable
calibrationParam  Calibration parameters  modifiable
resolution  Fixed-point number  modifiable
sensorState  Integer  read-only
signalValue  Fixed-point number  read-only
signalUnit  String  read-only
signalRange  Value range  modifiable
valueRange  Value range  modifiable
signalBias  Fixed-point number  modifiable
signalSampling  Enumerated  modifiable

dataLogger : DataLogger
attributetypemodifiable ?
logicalName  String  modifiable
advertisedValue  String  modifiable
currentRunIndex  Integer  read-only
timeUTC  UTC time  modifiable
recording  Enumerated  modifiable
autoStart  On/Off  modifiable
beaconDriven  On/Off  modifiable
clearHistory  Boolean  modifiable

files : Files
attributetypemodifiable ?
logicalName  String  modifiable
advertisedValue  String  modifiable
filesCount  Integer  read-only
freeSpace  Integer  read-only

7.3. Module control interface

This interface is identical for all Yoctopuce USB modules. It can be used to control the module global parameters, and to enumerate the functions provided by each module.

productName

Character string containing the commercial name of the module, as set by the factory.

serialNumber

Character string containing the serial number, unique and programmed at the factory. For a Yocto-SPI module, this serial number always starts with YSPIMK01. You can use the serial number to access a given module by software.

logicalName

Character string containing the logical name of the module, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access a given module. If two modules with the same logical name are in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

productId

USB device identifier of the module, preprogrammed to 102 at the factory.

productRelease

Release number of the module hardware, preprogrammed at the factory.

firmwareRelease

Release version of the embedded firmware, changes each time the embedded software is updated.

persistentSettings

State of persistent module settings: loaded from flash memory, modified by the user or saved to flash memory.

luminosity

Lighting strength of the informative leds (e.g. the Yocto-Led) contained in the module. It is an integer value which varies between 0 (leds turned off) and 100 (maximum led intensity). The default value is 50. To change the strength of the module leds, or to turn them off completely, you only need to change this value.

beacon

Activity of the localization beacon of the module.

upTime

Time elapsed since the last time the module was powered on.

usbCurrent

Current consumed by the module on the USB bus, in milli-amps.

rebootCountdown

Countdown to use for triggering a reboot of the module.

userVar

32bit integer variable available for user storage.

7.4. SerialPort function interface

The SerialPort function interface allows you to fully drive a Yoctopuce serial port, to send and receive data, and to configure communication parameters (baud rate, bit count, parity, flow control and protocol). Note that Yoctopuce serial ports are not exposed as virtual COM ports. They are meant to be used in the same way as all Yoctopuce devices.

logicalName

Character string containing the logical name of the SPI port, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the SPI port directly. If two SPI ports with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

advertisedValue

Short character string summarizing the current state of the SPI port, that is automatically advertised up to the parent hub. For a SPI port, the advertised value is a hexadecimal signature that changes after each character received. This signature is made of the lower 16 bits of the receive counter, plus the ASCII code of the last character received.

rxCount

Total number of bytes received since last reset.

txCount

Total number of bytes transmitted since last reset.

errCount

Total number of communication errors detected since last reset.

rxMsgCount

Total number of messages received since last reset.

txMsgCount

Total number of messages transmitted since last reset.

lastMsg

Last message fully received (for Line and Frame protocols).

currentJob

Name of the job file currently in use.

startupJob

Name of the job file to use when the device is powered on.

command

Magic attribute used to send commands to the serial port. If a command is not interpreted as expected, check the device logs.

voltageLevel

Voltage level used on the serial connection.

protocol

Type of protocol used on the serial link.

spiMode

Bit rate, SPI mode and bit order.

ssPolarity

SS line polarity.

shitftSampling

SDI/SDO phase shifting.

7.5. External power supply control interface

Yoctopuce application programming interface allows you to control the power ouput featured on some devices such as the Yocto-Serial.

logicalName

Character string containing the logical name of the power ouput control, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the power ouput control directly. If two dual power ouput controls with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

advertisedValue

Short character string summarizing the current state of the power ouput control, that will be automatically advertised up to the parent hub. For a dual power ouput control, the advertised value is the current voltage level: OFF, 3V3 ou 5V.

voltage

Power output voltage.

7.6. GenericSensor function interface

The YGenericSensor class allows you to read and configure Yoctopuce signal transducers. It inherits from YSensor class the core functions to read measurements, register callback functions, access to the autonomous datalogger. This class adds the ability to configure the automatic conversion between the measured signal and the corresponding engineering unit.

logicalName

Character string containing the logical name of the generic sensor, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the generic sensor directly. If two generic sensors with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

advertisedValue

Short character string summarizing the current state of the generic sensor, that is automatically advertised up to the parent hub. For a generic sensor, the advertised value is the current value of the measure.

unit

Short character string representing the measuring unit for the measured value.

currentValue

Current value of the measure, in the specified unit, as a floating point number.

lowestValue

Minimal value of the measure, in the specified unit, as a floating point number.

highestValue

Maximal value of the measure, in the specified unit, as a floating point number.

currentRawValue

Uncalibrated, unrounded raw value returned by the sensor, as a floating point number.

logFrequency

Datalogger recording frequency, or "OFF" when measures should not be stored in the data logger flash memory.

reportFrequency

Timed value notification frequency, or "OFF" when timed value notifications are disabled for this function.

calibrationParam

Extra calibration parameters (for instance to compensate for the effects of an enclosure), as an array of 16 bit words.

resolution

Measure resolution (i.e. precision of the numeric representation, not necessarily of the measure itself).

sensorState

Sensor health state (zero when a current measure is available).

signalValue

Current value of the electrical signal measured by the sensor, as a floating point number.

signalUnit

Short character string representing the measuring unit of the electrical signal used by the sensor.

signalRange

Electric signal range used by the sensor.

valueRange

Physical value range measured by the sensor, used to convert the signal.

signalBias

Electric signal bias for zero shift adjustment.

signalSampling

Signal sampling method to use.

7.7. DataLogger function interface

Yoctopuce sensors include a non-volatile memory capable of storing ongoing measured data automatically, without requiring a permanent connection to a computer. The DataLogger function controls the global parameters of the internal data logger.

logicalName

Character string containing the logical name of the data logger, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the data logger directly. If two data loggers with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

advertisedValue

Short character string summarizing the current state of the data logger, that is automatically advertised up to the parent hub. For a data logger, the advertised value is its recording state (ON or OFF).

currentRunIndex

Current run number, corresponding to the number of time the module was powered on with the dataLogger enabled at some point.

timeUTC

Current UTC time, in case it is desirable to bind an absolute time reference to the data stored by the data logger. This time must be set up by software.

recording

Activation state of the data logger. The data logger can be enabled and disabled at will, using this attribute, but its state on power on is determined by the autoStart persistent attribute. When the datalogger is enabled but not yet ready to record data, its state is set to PENDING.

autoStart

Automatic start of the data logger on power on. Setting this attribute ensures that the data logger is always turned on when the device is powered up, without need for a software command.

beaconDriven

Synchronize the sate of the localization beacon and the state of the data logger. If this attribute is set, it is possible to start the recording with the Yocto-button or the attribute beacon of the function YModule. In the same way, if the attribute recording is changed, the sate of the localization beacon is updated. Note: when this attribute is set the localization beacon pulses slower than usual.

clearHistory

Attribute that can be set to true to clear recorded data.

7.8. Files function interface

The filesystem interface makes it possible to store files on some devices, for instance to design a custom web UI (for networked devices) or to add fonts (on display devices).

logicalName

Character string containing the logical name of the filesystem, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the filesystem directly. If two filesystems with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

advertisedValue

Short character string summarizing the current state of the filesystem, that is automatically advertised up to the parent hub. For a filesystem, the advertised value is the number of files loaded in the filesystem.

filesCount

Number of files currently loaded in the filesystem.

freeSpace

Free space for uploading new files to the filesystem, in bytes.

7.9. What interface: Native, DLL or Service ?

There are several methods to control you Yoctopuce module by software.

Native control

In this case, the software driving your project is compiled directly with a library which provides control of the modules. Objectively, it is the simplest and most elegant solution for the end user. The end user then only needs to plug the USB cable and run your software for everything to work. Unfortunately, this method is not always available or even possible.


The application uses the native library to control the locally connected module

Native control by DLL

Here, the main part of the code controlling the modules is located in a DLL. The software is compiled with a small library which provides control of the DLL. It is the fastest method to code module support in a given language. Indeed, the "useful" part of the control code is located in the DLL which is the same for all languages: the effort to support a new language is limited to coding the small library which controls the DLL. From the end user stand point, there are few differences: one must simply make sure that the DLL is installed on the end user's computer at the same time as the main software.


The application uses the DLL to natively control the locally connected module

Control by service

Some languages do simply not allow you to easily gain access to the hardware layers of the machine. It is the case for Javascript, for instance. To deal with this case, Yoctopuce provides a solution in the form of a small piece of software called VirtualHub12. It can access the modules, and your application only needs to use a library which offers all necessary functions to control the modules via this VirtualHub. The end users will have to start the VirtualHub before running the project control software itself, unless they decide to install the hub as a service/deamon, in which case the VirtualHub starts automatically when the machine starts up.


The application connects itself to the VirtualHub to gain access to the module

The service control method comes with a non-negligible advantage: the application does not need to run on the machine on which the modules are connected. The application can very well be located on another machine which connects itself to the service to drive the modules. Moreover, the native libraries and DLL mentioned above are also able to connect themselves remotely to one or several machines running VirtualHub.


When a VirtualHub is used, the control application does not need to reside on the same machine as the module.

Whatever the selected programming language and the control paradigm used, programming itself stays strictly identical. From one language to another, functions bear exactly the same name, and have the same parameters. The only differences are linked to the constraints of the languages themselves.

Language Native  Native with DLL  Virtual hub 
C++
Objective-C -
Delphi -
Python -
VisualBasic .Net -
C# .Net -
EcmaScript / JavaScript - -
PHP - -
Java -
Java for Android -
Command line -

Support methods for different languages

Limitations of the Yoctopuce libraries

Natives et DLL libraries have a technical limitation. On the same computer, you cannot concurrently run several applications accessing Yoctopuce devices directly. If you want to run several projects on the same computer, make sure your control applications use Yoctopuce devices through a VirtualHub software. The modification is trivial: it is just a matter of parameter change in the yRegisterHub() call.

7.10. Programming, where to start?

At this point of the user's guide, you should know the main theoretical points of your Yocto-SPI. It is now time to practice. You must download the Yoctopuce library for your favorite programming language from the Yoctopuce web site13. Then skip directly to the chapter corresponding to the chosen programming language.

All the examples described in this guide are available in the programming libraries. For some languages, the libraries also include some complete graphical applications, with their source code.

When you have mastered the basic programming of your module, you can turn to the chapter on advanced programming that describes some techniques that will help you make the most of your Yocto-SPI.

8. Using the Yocto-SPI in command line

When you want to perform a punctual operation on your Yocto-SPI, such as reading a value, assigning a logical name, and so on, you can obviously use the Virtual Hub, but there is a simpler, faster, and more efficient method: the command line API.

The command line API is a set of executables, one by type of functionality offered by the range of Yoctopuce products. These executables are provided pre-compiled for all the Yoctopuce officially supported platforms/OS. Naturally, the executable sources are also provided14.

8.1. Installing

Download the command line API15. You do not need to run any setup, simply copy the executables corresponding to your platform/OS in a directory of your choice. You may add this directory to your PATH variable to be able to access these executables from anywhere. You are all set, you only need to connect your Yocto-SPI, open a shell, and start working by typing for example:

C:\>YSpiPort any set_spiMode "250000,2,msb"
C:\>YSpiPort any set_ssPolarity SSPOLARITY_ACTIVE_LOW
C:\>YSpiPort any set_protocol "Frame:5ms"
C:\>YSpiPort any writeHex "0c01"
C:\>YSpiPort any writeHex "09ff"
C:\>YSpiPort any writeHex "0b07"
C:\>YSpiPort any writeHex "0a0a"
C:\>YSpiPort any writeHex "0107"
C:\>YSpiPort any writeHex "0206"
C:\>YSpiPort any writeHex "0305"
C:\>YSpiPort any writeHex "0404"
 

To use the command API on Linux, you need either have root privileges or to define an udev rule for your system. See the Troubleshooting chapter for more details.

8.2. Use: general description

All the command line API executables work on the same principle. They must be called the following way


C:\>Executable [options] [target] command [parameter]

[options] manage the global workings of the commands, they allow you, for instance, to pilot a module remotely through the network, or to force the module to save its configuration after executing the command.

[target] is the name of the module or of the function to which the command applies. Some very generic commands do not need a target. You can also use the aliases "any" and "all", or a list of names separated by comas without space.

command is the command you want to run. Almost all the functions available in the classic programming APIs are available as commands. You need to respect neither the case nor the underlined characters in the command name.

[parameters] logically are the parameters needed by the command.

At any time, the command line API executables can provide a rather detailed help. Use for instance:


C:\>executable /help

to know the list of available commands for a given command line API executable, or even:


C:\>executable command /help

to obtain a detailed description of the parameters of a command.

8.3. Control of the SpiPort function

To control the SpiPort function of your Yocto-SPI, you need the YSpiPort executable file.

For instance, you can launch:

C:\>YSpiPort any set_spiMode "250000,2,msb"
C:\>YSpiPort any set_ssPolarity SSPOLARITY_ACTIVE_LOW
C:\>YSpiPort any set_protocol "Frame:5ms"
C:\>YSpiPort any writeHex "0c01"
C:\>YSpiPort any writeHex "09ff"
C:\>YSpiPort any writeHex "0b07"
C:\>YSpiPort any writeHex "0a0a"
C:\>YSpiPort any writeHex "0107"
C:\>YSpiPort any writeHex "0206"
C:\>YSpiPort any writeHex "0305"
C:\>YSpiPort any writeHex "0404"
 

This example uses the "any" target to indicate that we want to work on the first SpiPort function found among all those available on the connected Yoctopuce modules when running. This prevents you from having to know the exact names of your function and of your module.

But you can use logical names as well, as long as you have configured them beforehand. Let us imagine a Yocto-SPI module with the YSPIMK01-123456 serial number which you have called "MyModule", and its spiPort function which you have renamed "MyFunction". The five following calls are strictly equivalent (as long as MyFunction is defined only once, to avoid any ambiguity).


C:\>YSpiPort YSPIMK01-123456.spiPort describe

C:\>YSpiPort YSPIMK01-123456.MyFunction describe

C:\>YSpiPort MyModule.spiPort describe

C:\>YSpiPort MyModule.MyFunction describe

C:\>YSpiPort MyFunction describe

To work on all the SpiPort functions at the same time, use the "all" target.


C:\>YSpiPort all describe

For more details on the possibilities of the YSpiPort executable, use:


C:\>YSpiPort /help

8.4. Control of the module part

Each module can be controlled in a similar way with the help of the YModule executable. For example, to obtain the list of all the connected modules, use:


C:\>YModule inventory

You can also use the following command to obtain an even more detailed list of the connected modules:


C:\>YModule all describe

Each xxx property of the module can be obtained thanks to a command of the get_xxxx() type, and the properties which are not read only can be modified with the set_xxx() command. For example:


C:\>YModule YSPIMK01-12346 set_logicalName MonPremierModule

C:\>YModule YSPIMK01-12346 get_logicalName

Changing the settings of the module

When you want to change the settings of a module, simply use the corresponding set_xxx command. However, this change happens only in the module RAM: if the module restarts, the changes are lost. To store them permanently, you must tell the module to save its current configuration in its nonvolatile memory. To do so, use the saveToFlash command. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash method. For example:


C:\>YModule YSPIMK01-12346 set_logicalName MonPremierModule
C:\>YModule YSPIMK01-12346 saveToFlash

Note that you can do the same thing in a single command with the -s option.


C:\>YModule -s  YSPIMK01-12346 set_logicalName MonPremierModule

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

8.5. Limitations

The command line API has the same limitation than the other APIs: there can be only one application at a given time which can access the modules natively. By default, the command line API works in native mode.

You can easily work around this limitation by using a Virtual Hub: run the VirtualHub16 on the concerned machine, and use the executables of the command line API with the -r option. For example, if you use:


C:\>YModule  inventory

you obtain a list of the modules connected by USB, using a native access. If another command which accesses the modules natively is already running, this does not work. But if you run a Virtual Hub, and you give your command in the form:


C:\>YModule -r 127.0.0.1 inventory

it works because the command is not executed natively anymore, but through the Virtual Hub. Note that the Virtual Hub counts as a native application.

9. Using Yocto-SPI with EcmaScript / JavaScript

EcmaScript is the official name of the standardized version of the web-oriented programming language commonly referred to as JavaScript. This Yoctopuce library take advantages of advanced features introduced in EcmaScript 2015. It has therefore been named Library for EcmaScript to differentiate it from the previous Library for JavaScript, now deprecated in favor of this new version.

This library provides access to Yoctopuce devices for modern JavaScript engines. It can be used within a browser as well as with Node.js. The library will automatically detect upon initialization whether the runtime environment is a browser or a Node.js virtual machine, and use the most appropriate system libraries accordingly.

JavaScript is one of those languages which do not generally allow you to directly access the hardware layers of your computer. Therefore the library can only be used to access network-enabled devices (connected through a YoctoHub), or USB devices accessible through Yoctopuce TCP/IP to USB gateway, named VirtualHub.

9.1. Blocking I/O versus Asynchronous I/O in JavaScript

JavaScript is single-threaded by design. That means, if a program is actively waiting for the result of a network-based operation such as reading from a sensor, the whole program is blocked. In browser environments, this can even completely freeze the user interface. For this reason, the use of blocking I/O in JavaScript is strongly discouraged nowadays, and blocking network APIs are getting deprecated everywhere.

Instead of using parallel threads, JavaScript relies on asynchronous I/O to handle operations with a possible long timeout: whenever a long I/O call needs to be performed, it is only triggered and but then the code execution flow is terminated. The JavaScript engine is therefore free to handle other pending tasks, such as UI. Whenever the pending I/O call is completed, the system invokes a callback function with the result of the I/O call to resume execution of the original execution flow.

When used with plain callback functions, as pervasive in Node.js libraries, asynchronous I/O tend to produce code with poor readability, as the execution flow is broken into many disconnected callback functions. Fortunately, new methods have emerged recently to improve that situation. In particular, the use of Promise objects to abstract and work with asynchronous tasks helps a lot. Any function that makes a long I/O operation can return a Promise, which can be used by the caller to chain subsequent operations in the same flow. Promises are part of EcmaScript 2015 standard.

Promise objects are good, but what makes them even better is the new async / await keywords to handle asynchronous I/O:

Long story made short, async and await make it possible to write EcmaScript code with all benefits of asynchronous I/O, but without breaking the code flow. It is almost like multi-threaded execution, except that control switch between pending tasks only happens at places where the await keyword appears.

We have therefore chosen to write our new EcmaScript library using Promises and async functions, so that you can use the friendly await syntax. To keep it easy to remember, all public methods of the EcmaScript library are async, i.e. return a Promise object, except:

One important thing to note: as of early 2016, async and await are not yet part of current EcmaScript standard. They are stage 3 features, meaning they are on track for inclusion in future versions of the standard, but they are not yet officially in. There are however tools that allow them to be used today, by translating them automatically into standard JavaScript code supported by all JavaScript engines. This will be covered in the next sections

9.2. Using Yoctopuce library for EcmaScript

Go to the Yoctopuce web site and download the following items:

Extract the library files in a folder of your choice, you will find many of examples in it. Connect your modules and start the VirtualHub software. You do not need to install any driver.

Prerequisites for the development environment

As explained in previous section, asynchronous communication with the devices is handled across the whole library using Promise objects. This makes it possible to use the new async / await non-blocking syntax for asynchronous I/O. As the async / await syntax is not yet directly available in current JavaScript engines, your applications using this library will most probably need to be transpiled to more standard JavaScript to run. This wîll be done using command-line tools based on Node.js, even when creating a browser application. So you will need to install Node.js (including the package manager npm) to develop software using Yoctopuce library for EcmaScript.

So download and install on your development machine the current version of Node.js from the official web site: http://nodejs.org.

Once this is done, you have several options:

  1. The easiest way to do that is to use JSPM, as described in the next sections. To simplify the instructions, we have created separate sections on how to for write Node.js apps and browser apps.
  2. Alternatively, you can run Babel to transpile your source code explicitly. Your favorite editor might have a watcher that runs Babel automatically each time you change the source code. Make sure you enable stage-3 extensions.
  3. Or you can write your code in pure EcmaScript 2015 and handle Promises explicitly, instead of using async / await. You will find more on that approach later down.

Using the library for node.js, with JSPM

NOTE: This version of the library is designed for jspm 0.17 (still in beta, but works very well nevertheless).

If not yet done, start by installing jspm on your system. It is very easy, as npm will take care of the download for you. Simply run the following command:


npm install jspm@beta -g

Now you can pick any of the examples in the example_nodejs directory (for instance example_nodejs/Doc-Inventory). Go to that directory. You will see that it include an application description file (package.json), a jspm configuration file (jspm.config.js) and the source code (src/demo.js). To download and setup the libraries needed by this example, run:


npm install
jspm install

Once done, you can start the example file using


jspm run src/demo.js

The jspm run command will actually transpile the example code into JavaScript code that node can understand, and execute it with node.js.

When you go into production, you can build your application once for all to avoid requiring jspm on the target machine. In order to do this, just run:


jspm build src/demo.js --node

This will create a single file named build.js, that includes everything needed to run your demo.js (even if your application is made of multiple source files). You can then execute it simply using:


node build.js

Once built in this way, you can also send your application to any standard node.js hosting server.

Using the library in browser code, with JSPM

NOTE: This version of the library is designed for jspm 0.17 (still in beta, but works very well nevertheless).

If not yet done, start by installing jspm on your system. It is very easy, as npm will take care of the download for you. Simply run the following command:


npm install jspm@beta -g

Now you can pick any of the examples in the example_html directory (for instance example_html/Doc-Inventory). Go to that directly. You will see that it include an application description file (package.json), a jspm configuration file (jspm.config.js), a browser-specific jspm configuration file (jspm.browser.js) and the source code (src/demo.js). To download and setup the libraries needed by this example, run:


npm install
jspm install

Then make sure the directory on which you have your project is available through a web server (you can specify the base URL injspm.browser.js), and open inventory.html (or demo.html, depending on the example that you chose) in your browser through your HTTP server.

Note that our pre-transpiled library code is optimized for running quickly with recent JS engines (Chrome 47, Firefox 45, Opera 36, Edge 13, Safari 9). If you need to support older browsers, you can import our library in source form rather than pre-transpiled form. This will takes a bit longer to load initially, but will then run on any EcmaScript-5 browser. In order to do so, in the demo.js code, change the import statement as below to point to the source library:


import { YAPI, YModule, YErrMsg } from 'yoctolib-es/src'

To avoid transpiling your JS code each time you load the page and to load all the individual shims, you can also ask jspm to build a monolithic js file that contains everything needed for your project, minified to reduce file transfers, like this:


jspm build --minify src/demo.js demo-sfx.js

Now you can replace all include lines in inventory.html by a single include of demo-sfx.js.

You can further reduce the amount of code downloaded by importing just the submodules that you need from our library, instead of including it completely. For instance, in the inventory example, you could use


import { YAPI, YModule, YErrMsg } from 'yoctolib-es/yocto_api'

or to import in source form:


import { YAPI, YModule, YErrMsg } from 'yoctolib-es/src/yocto_api'

Creating a Yoctopuce application from scratch, with JSPM

Rather than starting from one of our examples, you can also create a "blank" JSPM application using our library from scratch using the following commands:


npm install jspm@beta --save-dev
jspm init . -y
jspm install npm:yoctolib-es
npm install ws --save

This creates all necessary configuration files in your directory to run the Yoctopuce EcmaScript 2015 library with jspm. If you remove the -y argument on the command line, you will be prompted for individual settings such as preferred directory names, etc.

Using the library without JSPM

Yoctopuce library for EcmaScript ships with pre-transpiled files for the V8 engine used by Node.JS versions 4+, Google Chrome, as well as for Firefox. It is therefore possible to use it without JSPM, if you can live without the convenient async/await syntax (or if you transpile your async/await code yourself using Babel).

In order to use the library in node.js WITHOUT jspm, just install yoctolib-es from npm repository into your project:


npm install yoctolib-es --save

You can then use node require() function to load the package in your node.js code, and use all functions taking into account that they all return promises. You will find an example of this approach in example_nodejs/Prog-VanillaNodeJs.

Backward-compatibility with the old JavaScript library

This new library is not fully backward-compatible with the old JavaScript library, because there is no way to transparently map the old blocking API to the new asynchronous API. The method names however are the same, and old synchronous code can easily be made asynchronous just by adding the proper await keywords before the method calls. For instance, simply replace:


beaconState = module.get_beacon();

by


beaconState = await module.get_beacon();

Apart from a few exceptions, most XXX_async redundant methods have been removed as well, as they would have introduced confusion on the proper way of handling asynchronous behaviors. It is however very simple to get an async method to invoke a callback upon completion, using the returned Promise object. For instance, you can replace:


module.get_beacon_async(callback, myContext);

by


module.get_beacon().then(function(res) { callback(myContext, module, res); });

In some cases, it might be desirable to get a sensor value using a method identical to the old synchronous methods (without using Promises), even if it returns a slightly outdated cached value since I/O is not possible. For this purpose, the EcmaScript library introduce new classes called synchronous proxies. A synchronous proxy is an object that mirrors the most recent state of the connected class, but can be read using regular synchronous function calls. For instance, instead of writing:


async function logInfo(module)
{
    console.log('Name: '+await module.get_logicalName());
    console.log('Beacon: '+await module.get_beacon());
}

...
logInfo(myModule);
...

you can use:


function logInfoProxy(moduleSyncProxy)
{
    console.log('Name: '+moduleProxy.get_logicalName());
    console.log('Beacon: '+moduleProxy.get_beacon());
}

logInfoSync(await myModule.get_syncProxy());

You can also rewrite this last asynchronous call as:


myModule.get_syncProxy().then(logInfoProxy);

9.3. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a JavaScript code snipplet to use the SpiPort function.


import { YAPI, YErrorMsg, YSpiPort } from 'yoctolib-es';

// Get access to your device, through the VirtualHub running locally
await YAPI.RegisterHub('127.0.0.1');
var spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort");

// Check that the module is online to handle hot-plug
if(await spiport.isOnline())
{
    // Use spiport.set_spiMode()
    [...]
}

Let us look at these lines in more details.

YAPI and YSpiPort Import

These two import provide access to functions allowing you to manage Yoctopuce modules. YAPI is always needed, YSpiPort.js is necessary to manage modules containing a SPI port, such as Yocto-SPI. Other imports can be useful in other cases, such as YModule which can let you enumerate any type of Yoctopuce device.

YAPI.RegisterHub

The RegisterHub method allows you to indicate on which machine the Yoctopuce modules are located, more precisely on which machine the VirtualHub software is running. In our case, the 127.0.0.1:4444 address indicates the local machine, port 4444 (the standard port used by Yoctopuce). You can very well modify this address, and enter the address of another machine on which the VirtualHub software is running, or of a YoctoHub. If the host cannot be reached, this function will trigger an exception.

YSpiPort.FindSpiPort

The FindSpiPort method allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can also use logical names, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort")
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.MaFonction")
spiport = YSpiPort.FindSpiPort("MonModule.spiPort")
spiport = YSpiPort.FindSpiPort("MonModule.MaFonction")
spiport = YSpiPort.FindSpiPort("MaFonction")

YSpiPort.FindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by FindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by YSpiPort.FindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by YSpiPort.FindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Open a command window (a terminal, a shell...) and go into the directory example_node/Doc-GettingStarted-Yocto-SPI within Yoctopuce EcmaScript library. In there, you will find a subdirectory src with the sample code below, which uses the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

If your Yocto-SPI is not connected on the host running the browser, replace in the example the address 127.0.0.1 by the IP address of the host on which the Yocto-SPI is connected and where you run the VirtualHub.

import { YAPI, YErrorMsg, YSpiPort } from 'yoctolib-es';

async function startDemo(args)
{
    await YAPI.LogUnhandledPromiseRejections();
    await YAPI.DisableExceptions();

    // Setup the API to use the VirtualHub on local machine
    let errmsg = new YErrorMsg();
    if(await YAPI.RegisterHub('127.0.0.1', errmsg) != YAPI.SUCCESS) {
        console.log('Cannot contact VirtualHub on 127.0.0.1: '+errmsg.msg);
        return;
    }
   
    // Select the SPI interface to use
    let target;
    if(args[0] == "any") {
        let anySpi = YSpiPort.FirstSpiPort();
        if (anySpi == null) {
            console.log("No module connected (check USB cable)\n");
            process.exit(1);
        }
        let module = await anySpi.get_module();
        target = await module.get_serialNumber();
    } else {
        target = args[0];
    }
    let value = parseInt(args[1]);

    let spiPort = YSpiPort.FindSpiPort(target+'.spiPort');

    if(await spiPort.isOnline()) {
        // sample code driving MAX7219 7-segment display driver
        // such as SPI7SEGDISP8.56 from www.embedded-lab.com
        await spiPort.set_spiMode("250000,2,msb");
        await spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW);
        await spiPort.set_protocol("Frame:5ms");
        await spiPort.reset();
        console.log("****************************");
        console.log("* make sure voltage levels *");
        console.log("* are properly configured  *");
        console.log("****************************");
        // initialize MAX7219
        await spiPort.writeHex('0c01'); // Exit from shutdown state
        await spiPort.writeHex('09ff'); // Enable BCD for all digits
        await spiPort.writeHex('0b07'); // Enable digits 0-7 (=8 in total)
        await spiPort.writeHex('0a0a'); // Set medium brightness
        for(let i = 1; i <= 8; i++) {
            let digit = value % 10;
            await spiPort.writeArray([i, digit]);
            value = parseInt(value / 10);
        }
    } else {
        console.log("Module not connected (check identification and USB cable)\n");
    }

    YAPI.FreeAPI();
}

if(process.argv.length < 5) {
    console.log("usage: jspm run src/demo.js <serial_number> <value>");
    console.log("       jspm run src/demo.js <logical_name>  <value>");
    console.log("       jspm run src/demo.js any <value>    (use any discovered device)");
} else {
    startDemo(process.argv.slice(process.argv.length - 2));
}

 

As explained at the beginning of this chapter, you need to have Node.js and jspm installed to try this example. When done, you can type the following two commands to automatically download and install the dependencies for building this example:


npm install
jspm install
You can the start the sample code within Node.js using the following command, replacing the [...] by the arguments that you want to pass to the demo code:

jspm run src/demo.js [...]

Same example, but this time running in a browser

If you want to see how to use the library within a browser, switch to the directory example_html/Doc-GettingStarted-Yocto-SPI. You will find there a subdirectory src as well with a very similar source code (below), but with a few changes compared to the Node.js version since it has to interact through an HTML page rather than through the JavaScript console.

import { YAPI, YErrorMsg, YSpiPort } from 'yoctolib-es';

var spiPort;

async function startDemo()
{
    await YAPI.LogUnhandledPromiseRejections();
    await YAPI.DisableExceptions();

    // Setup the API to use the VirtualHub on local machine
    let errmsg = new YErrorMsg();
    if(await YAPI.RegisterHub('127.0.0.1', errmsg) != YAPI.SUCCESS) {
        alert('Cannot contact VirtualHub on 127.0.0.1: '+errmsg.msg);
    }
    refresh();
}

async function refresh()
{
    let serial = document.getElementById('serial').value;
    if(serial == '') {
        // by default use any connected module suitable for the demo
        let anySpi = YSpiPort.FirstSpiPort();
        if(anySpi) {
            let module = await anySpi.module();
            serial = await module.get_serialNumber();
            document.getElementById('serial').value = serial;
        }
    }
    spiPort = YSpiPort.FindSpiPort(serial+'.spiPort');
    if(await spiPort.isOnline()) {
        document.getElementById('msg').value = '';
        await spiPort.set_spiMode("250000,2,msb");
        await spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW);
        await spiPort.set_protocol("Frame:5ms");
        await spiPort.reset();
        await spiPort.writeHex('0c01'); // Exit from shutdown state
        await spiPort.writeHex('09ff'); // Enable BCD for all digits
        await spiPort.writeHex('0b07'); // Enable digits 0-7 (=8 in total)
        await spiPort.writeHex('0a0a'); // Set medium brightness
    } else {
        document.getElementById('msg').value = 'Module not connected';
        setTimeout(refresh, 500);
    }
}

window.updateValue = function(value)
{
    value = parseInt(value);
    for(let i = 1; i <= 8; i++) {
        let digit = value % 10;
        spiPort.writeArray([i, digit]);
        value = parseInt(value / 10);
    }
};

startDemo();
 

At the root of this example you will also find a file demo.html which contains the UI elements for the demo code.

<!DOCTYPE html>
<html>
<head>
  <title>Hello World</title>
  <script src='jspm_packages/system.js'></script>
  <script src='jspm.browser.js'></script>
  <script src='jspm.config.js'></script>
  <script>
    System.import('app/helloworld.js');
  </script>
  <!-- When going in production, you can generate a self-contained js file using

 jspm build --minify src/demo.js demo-sfx.js

 and replace the 6 lines above by just this one:

 <script src='demo-sfx.js'></script>
 -->
</head>
<body>
Module to use: <input id='serial'>
<input id='msg' style='color:red;border:none;' readonly><br>
Value to display: <input onkeyup='updateValue(this.value)'><br>
<i>Note: Make sure voltage are configured properly!</i>
</body>
</html>
 

As above, the two following commands will download and install all dependencies for building this example:


npm install
jspm install

You can now publish this directory on a Web server to test the example through a web browser. In order to let the loader find its files, you will have to point the baseURL parameter in jspm.browser.js file to the path within the web server root to reach the demo project. For instance, if you open the example using URL http://127.0.0.1/EcmaScript/example_html/Doc-GettingStarted-Yocto-SPI/demo.html then the beginning of your jspm.browser.js file should look like:


SystemJS.config({
  baseURL: "/EcmaScript/example_html/Doc-GettingStarted-Yocto-SPI/",
  ...
}

If you prefer to open the demo code as a local file rather than through a web server, or if you would like the example to load as a single JavaScript file rather than as dynamically loaded modules, you can build it with the command:


jspm build --minify src/demo.js demo-sfx.js

This will create a single JavaScript file named demo-sfx.js in the root directory of the project, that can be included directly in the HTML file instead of the 6 script lines:


<script src='demo-sfx.js'></script>

Once your project is built in this way, the example can be opened by a browser directly from the local disk.

9.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

import { YAPI, YErrorMsg, YModule } from 'yoctolib-es';

async function startDemo(args)
{
    await YAPI.LogUnhandledPromiseRejections();

    // Setup the API to use the VirtualHub on local machine
    let errmsg = new YErrorMsg();
    if(await YAPI.RegisterHub('127.0.0.1', errmsg) != YAPI.SUCCESS) {
        console.log('Cannot contact VirtualHub on 127.0.0.1: '+errmsg.msg);
        return;
    }

    // Select the relay to use
    let module = YModule.FindModule(args[0]);
    if(await module.isOnline()) {
        if(args.length > 1) {
            if(args[1] == 'ON') {
                await module.set_beacon(YModule.BEACON_ON);
            } else {
                await module.set_beacon(YModule.BEACON_OFF);
            }
        }
        console.log('serial:       '+await module.get_serialNumber());
        console.log('logical name: '+await module.get_logicalName());
        console.log('luminosity:   '+await module.get_luminosity()+'%');
        console.log('beacon:       '+(await module.get_beacon()==YModule.BEACON_ON?'ON':'OFF'));
        console.log('upTime:       '+parseInt(await module.get_upTime()/1000)+' sec');
        console.log('USB current:  '+await module.get_usbCurrent()+' mA');
        console.log('logs:');
        console.log(await module.get_lastLogs());
    } else {
        console.log("Module not connected (check identification and USB cable)\n");
    }
    YAPI.FreeAPI();
}

if(process.argv.length < 3) {
    console.log("usage: jspm run src/demo.js <serial or logicalname> [ ON | OFF ]");
} else {
    startDemo(process.argv.slice(process.argv.length - 3));
}
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

import { YAPI, YErrorMsg, YModule } from 'yoctolib-es';

async function startDemo(args)
{
    await YAPI.LogUnhandledPromiseRejections();

    // Setup the API to use the VirtualHub on local machine
    let errmsg = new YErrorMsg();
    if(await YAPI.RegisterHub('127.0.0.1', errmsg) != YAPI.SUCCESS) {
        console.log('Cannot contact VirtualHub on 127.0.0.1: '+errmsg.msg);
        return;
    }
   
    // Select the relay to use
    let module = YModule.FindModule(args[0]);
    if(await module.isOnline()) {
        if(args.length > 1) {
            var newname = args[1];
            if (!await YAPI.CheckLogicalName(newname)) {
                console.log("Invalid name (" + newname + ")");
                process.exit(1);
            }
            await module.set_logicalName(newname);
            await module.saveToFlash();
        }
        console.log('Current name: '+await module.get_logicalName());
    } else {
        console.log("Module not connected (check identification and USB cable)\n");
    }
    YAPI.FreeAPI();
}

if(process.argv.length < 3) {
    console.log("usage: jspm run src/demo.js <serial> [newLogicalName]");
} else {
    startDemo(process.argv.slice(process.argv.length - 3));
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.FirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

import { YAPI, YModule, YErrorMsg } from 'yoctolib-es';

async function startDemo()
{
    await YAPI.LogUnhandledPromiseRejections();
    await YAPI.DisableExceptions();

    // Setup the API to use the VirtualHub on local machine
    let errmsg = new YErrorMsg();
    if (await YAPI.RegisterHub('http://127.0.0.1:4444/', errmsg) != YAPI.SUCCESS) {
        console.log('Cannot contact VirtualHub on 127.0.0.1');
        return;
    }
    refresh();
}

async function refresh()
{
    try {
        let errmsg = new YErrorMsg();
        await YAPI.UpdateDeviceList(errmsg);

        let module = YModule.FirstModule();
        while(module) {
            let line = await module.get_serialNumber();
            line += '(' + (await module.get_productName()) + ')';
            console.log(line);
            module = module.nextModule();
        }
        setTimeout(refresh, 500);
    } catch(e) {
        console.log(e);
    }
}

try {
    startDemo();
} catch(e) {
    console.log(e);
}
 

9.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

10. Using Yocto-SPI with PHP

PHP is, like Javascript, an atypical language when interfacing with hardware is at stakes. Nevertheless, using PHP with Yoctopuce modules provides you with the opportunity to very easily create web sites which are able to interact with their physical environment, and this is not available to every web server. This technique has a direct application in home automation: a few Yoctopuce modules, a PHP server, and you can interact with your home from anywhere on the planet, as long as you have an internet connection.

PHP is one of those languages which do not allow you to directly access the hardware layers of your computer. Therefore you need to run a virtual hub on the machine on which your modules are connected.

To start your tests with PHP, you need a PHP 5.3 (or more) server19, preferably locally on you machine. If you wish to use the PHP server of your internet provider, it is possible, but you will probably need to configure your ADSL router for it to accept and forward TCP request on the 4444 port.

10.1. Getting ready

Go to the Yoctopuce web site and download the following items:

Decompress the library files in a folder of your choice accessible to your web server, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.

10.2. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a PHP code snipplet to use the SpiPort function.


include('yocto_api.php');
include('yocto_spiport.php');

// Get access to your device, through the VirtualHub running locally
yRegisterHub('http://127.0.0.1:4444/',$errmsg);
$spiport = yFindSpiPort("YSPIMK01-123456.spiPort");

// Check that the module is online to handle hot-plug
if(spiport->isOnline())
{
    // Use spiport->set_spiMode(), ...
}

Let's look at these lines in more details.

yocto_api.php and yocto_spiport.php

These two PHP includes provides access to the functions allowing you to manage Yoctopuce modules. yocto_api.php must always be included, yocto_spiport.php is necessary to manage modules containing a SPI port, such as Yocto-SPI.

yRegisterHub

The yRegisterHub function allows you to indicate on which machine the Yoctopuce modules are located, more precisely on which machine the VirtualHub software is running. In our case, the 127.0.0.1:4444 address indicates the local machine, port 4444 (the standard port used by Yoctopuce). You can very well modify this address, and enter the address of another machine on which the VirtualHub software is running.

yFindSpiPort

The yFindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


$spiport = yFindSpiPort("YSPIMK01-123456.spiPort");
$spiport = yFindSpiPort("YSPIMK01-123456.MyFunction");
$spiport = yFindSpiPort("MyModule.spiPort");
$spiport = yFindSpiPort("MyModule.MyFunction");
$spiport = yFindSpiPort("MyFunction");

yFindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by yFindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by yFindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by yFindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Open your preferred text editor22, copy the code sample below, save it with the Yoctopuce library files in a location which is accessible to you web server, then use your preferred web browser to access this page. The code is also provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

UNABLE TO INCLUDE
/yoctoprod/projects/yocto-spi/public/examples/php/helloworld.php

10.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

<HTML>
<HEAD>
 <TITLE>Module Control</TITLE>
</HEAD>
<BODY>
<FORM method='get'>
<?php
  include('yocto_api.php');

  // Use explicit error handling rather than exceptions
  yDisableExceptions();

  // Setup the API to use the VirtualHub on local machine
  if(yRegisterHub('http://127.0.0.1:4444/',$errmsg) != YAPI_SUCCESS) {
      die("Cannot contact VirtualHub on 127.0.0.1 : ".$errmsg);
  }

  @$serial = $_GET['serial'];
  if ($serial != '') {
      // Check if a specified module is available online
      $module = yFindModule("$serial");  
      if (!$module->isOnline()) {
          die("Module not connected (check serial and USB cable)");
      }
  } else {
      // or use any connected module suitable for the demo
      $module = yFirstModule();
      if($module) { // skip VirtualHub
          $module = $module->nextModule();
      }
      if(is_null($module)) {
          die("No module connected (check USB cable)");
      } else {
          $serial = $module->get_serialnumber();
      }
  }
  Print("Module to use: <input name='serial' value='$serial'><br>");

  if (isset($_GET['beacon'])) {
      if ($_GET['beacon']=='ON')
          $module->set_beacon(Y_BEACON_ON);
      else  
          $module->set_beacon(Y_BEACON_OFF);
  }          
  printf('serial: %s<br>',$module->get_serialNumber());
  printf('logical name: %s<br>',$module->get_logicalName());
  printf('luminosity: %s<br>',$module->get_luminosity());
  print('beacon: ');
  if($module->get_beacon() == Y_BEACON_ON) {
      printf("<input type='radio' name='beacon' value='ON' checked>ON ");
      printf("<input type='radio' name='beacon' value='OFF'>OFF<br>");
  } else {
      printf("<input type='radio' name='beacon' value='ON'>ON ");
      printf("<input type='radio' name='beacon' value='OFF' checked>OFF<br>");
  }
  printf('upTime: %s sec<br>',intVal($module->get_upTime()/1000));
  printf('USB current: %smA<br>',$module->get_usbCurrent());
  printf('logs:<br><pre>%s</pre>',$module->get_lastLogs());
?>  
<input type='submit' value='refresh'>
</FORM>
</BODY>
</HTML>
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

<HTML>
<HEAD>
 <TITLE>save settings</TITLE>
<BODY>
<FORM method='get'>
<?php
  include('yocto_api.php');
 
  // Use explicit error handling rather than exceptions
  yDisableExceptions();

  // Setup the API to use the VirtualHub on local machine
  if(yRegisterHub('http://127.0.0.1:4444/',$errmsg) != YAPI_SUCCESS) {
      die("Cannot contact VirtualHub on 127.0.0.1");
  }

  @$serial = $_GET['serial'];
  if ($serial != '') {
      // Check if a specified module is available online
      $module = yFindModule("$serial");  
      if (!$module->isOnline()) {
          die("Module not connected (check serial and USB cable)");
      }
  } else {
      // or use any connected module suitable for the demo
      $module = yFirstModule();
      if($module) { // skip VirtualHub
          $module = $module->nextModule();
      }
      if(is_null($module)) {
          die("No module connected (check USB cable)");
      } else {
          $serial = $module->get_serialnumber();
      }
  }
  Print("Module to use: <input name='serial' value='$serial'><br>");

  if (isset($_GET['newname'])){
      $newname = $_GET['newname'];
      if (!yCheckLogicalName($newname))
          die('Invalid name');
      $module->set_logicalName($newname);
      $module->saveToFlash();
  }
  printf("Current name: %s<br>", $module->get_logicalName());
  print("New name: <input name='newname' value='' maxlength=19><br>");
?>
<input type='submit'>
</FORM>
</BODY>
</HTML>
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

<HTML>
<HEAD>
 <TITLE>inventory</TITLE>
</HEAD>
<BODY>
<H1>Device list</H1>
<TT>
<?php
    include('yocto_api.php');
    yRegisterHub("http://127.0.0.1:4444/");
    $module   = yFirstModule();
    while (!is_null($module)) {
        printf("%s (%s)<br>", $module->get_serialNumber(),
               $module->get_productName());
        $module=$module->nextModule();
    }
?>
</TT>
</BODY>
</HTML>
 

10.4. HTTP callback API and NAT filters

The PHP library is able to work in a specific mode called HTTP callback Yocto-API. With this mode, you can control Yoctopuce devices installed behind a NAT filter, such as a DSL router for example, and this without needing to open a port. The typical application is to control Yoctopuce devices, located on a private network, from a public web site.

The NAT filter: advantages and disadvantages

A DSL router which translates network addresses (NAT) works somewhat like a private phone switchboard (a PBX): internal extensions can call each other and call the outside; but seen from the outside, there is only one official phone number, that of the switchboard itself. You cannot reach the internal extensions from the outside.


Typical DSL configuration: LAN machines are isolated from the outside by the DSL router

Transposed to the network, we have the following: appliances connected to your home automation network can communicate with one another using a local IP address (of the 192.168.xxx.yyy type), and contact Internet servers through their public address. However, seen from the outside, you have only one official IP address, assigned to the DSL router only, and you cannot reach your network appliances directly from the outside. It is rather restrictive, but it is a relatively efficient protection against intrusions.


Responses from request from LAN machines are routed.


But requests from the outside are blocked.

Seeing Internet without being seen provides an enormous security advantage. However, this signifies that you cannot, a priori, set up your own web server at home to control a home automation installation from the outside. A solution to this problem, advised by numerous home automation system dealers, consists in providing outside visibility to your home automation server itself, by adding a routing rule in the NAT configuration of the DSL router. The issue of this solution is that it exposes the home automation server to external attacks.

The HTTP callback API solves this issue without having to modify the DSL router configuration. The module control script is located on an external site, and it is the VirtualHub which is in charge of calling it a regular intervals.


The HTTP callback API uses the VirtualHub which initiates the requests.

Configuration

The callback API thus uses the VirtualHub as a gateway. All the communications are initiated by the VirtualHub. They are thus outgoing communications and therefore perfectly authorized by the DSL router.

You must configure the VirtualHub so that it calls the PHP script on a regular basis. To do so:

  1. Launch a VirtualHub
  2. Access its interface, usually 127.0.0.1:4444
  3. Click on the configure button of the line corresponding to the VirtualHub itself
  4. Click on the edit button of the Outgoing callbacks section


Click on the "configure" button on the first line


Click on the "edit" button of the "Outgoing callbacks" section


And select "Yocto-API callback".

You then only need to define the URL of the PHP script and, if need be, the user name and password to access this URL. Supported authentication methods are basic and digest. The second method is safer than the first one because it does not allow transfer of the password on the network.

Usage

From the programmer standpoint, the only difference is at the level of the yRegisterHub function call. Instead of using an IP address, you must use the callback string (or http://callback which is equivalent).


include("yocto_api.php");
yRegisterHub("callback");

The remainder of the code stays strictly identical. On the VirtualHub interface, at the bottom of the configuration window for the HTTP callback API , there is a button allowing you to test the call to the PHP script.

Be aware that the PHP script controlling the modules remotely through the HTTP callback API can be called only by the VirtualHub. Indeed, it requires the information posted by the VirtualHub to function. To code a web site which controls Yoctopuce modules interactively, you must create a user interface which stores in a file or in a database the actions to be performed on the Yoctopuce modules. These actions are then read and run by the control script.

Common issues

For the HTTP callback API to work, the PHP option allow_url_fopen must be set. Some web site hosts do not set it by default. The problem then manifests itself with the following error:

error: URL file-access is disabled in the server configuration

To set this option, you must create, in the repertory where the control PHP script is located, an .htaccess file containing the following line:
php_flag "allow_url_fopen" "On"
Depending on the security policies of the host, it is sometimes impossible to authorize this option at the root of the web site, or even to install PHP scripts receiving data from a POST HTTP. In this case, place the PHP script in a subdirectory.

Limitations

This method that allows you to go through NAT filters cheaply has nevertheless a price. Communications being initiated by the VirtualHub at a more or less regular interval, reaction time to an event is clearly longer than if the Yoctopuce modules were driven directly. You can configure the reaction time in the specific window of the VirtualHub, but it is at least of a few seconds in the best case.

The HTTP callback Yocto-API mode is currently available in PHP and Node.JS only.

10.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

11. Using Yocto-SPI with C++

C++ is not the simplest language to master. However, if you take care to limit yourself to its essential functionalities, this language can very well be used for short programs quickly coded, and it has the advantage of being easily ported from one operating system to another. Under Windows, all the examples and the project models are tested with Microsoft Visual Studio 2010 Express, freely available on the Microsoft web site23. Under Mac OS X, all the examples and project models are tested with XCode 4, available on the App Store. Moreover, under Max OS X and under Linux, you can compile the examples using a command line with GCC using the provided GNUmakefile. In the same manner under Windows, a Makefile allows you to compile examples using a command line, fully knowing the compilation and linking arguments.

Yoctopuce C++ libraries24 are integrally provided as source files. A section of the low-level library is written in pure C, but you should not need to interact directly with it: everything was done to ensure the simplest possible interaction from C++. The library is naturally also available as binary files, so that you can link it directly if you prefer.

You will soon notice that the C++ API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface. You will find in the last section of this chapter all the information needed to create a wholly new project linked with the Yoctopuce libraries.

11.1. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a C++ code snipplet to use the SpiPort function.


#include "yocto_api.h"
#include "yocto_spiport.h"

[...]
String  errmsg;
YSpiPort *spiport;

// Get access to your device, connected locally on USB for instance
yRegisterHub("usb", errmsg);
spiport = yFindSpiPort("YSPIMK01-123456.spiPort");

// Hot-plug is easy: just check that the device is online
if(spiport->isOnline())
{
    // Use spiport->set_spiMode(), ...
}

Let's look at these lines in more details.

yocto_api.h et yocto_spiport.h

These two include files provide access to the functions allowing you to manage Yoctopuce modules. yocto_api.h must always be used, yocto_spiport.h is necessary to manage modules containing a SPI port, such as Yocto-SPI.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindSpiPort

The yFindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


YSpiPort *spiport = yFindSpiPort("YSPIMK01-123456.spiPort");
YSpiPort *spiport = yFindSpiPort("YSPIMK01-123456.MyFunction");
YSpiPort *spiport = yFindSpiPort("MyModule.spiPort");
YSpiPort *spiport = yFindSpiPort("MyModule.MyFunction");
YSpiPort *spiport = yFindSpiPort("MyFunction");

yFindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by yFindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by yFindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by yFindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Launch your C++ environment and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library. If you prefer to work with your favorite text editor, open the file main.cpp, and type make to build the example when you are done.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

#include "yocto_api.h"
#include "yocto_spiport.h"
#include <iostream>
#include <stdlib.h>

using namespace std;

static void usage(void)
{
    cout << "usage: demo <serial_number> <value>" << endl;
    cout << "       demo <logical_name>  <value>" << endl;
    cout << "       demo any  <value>   (use any discovered device)" << endl;
    u64 now = yGetTickCount();
    while (yGetTickCount()-now<3000) {
        // wait 3 sec to show the message
    }
    exit(1);
}

int main(int argc, const char * argv[])
{
    string errmsg;
    string target;
    int    value;
    YSpiPort *spiPort;

    if (argc < 3) {
        usage();
    }
    target = (string) argv[1];
    value = (int)atol(argv[2]);
   
    // Setup the API to use local USB devices
    if (yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    if (target == "any") {
        spiPort = yFirstSpiPort();
        if (spiPort == NULL) {
            cerr << "No module connected (check USB cable)"<<endl;
            return 1;
        }
    } else {
        target = (string) argv[1];
        spiPort = yFindSpiPort(target + ".spiPort");
        if (!spiPort->isOnline()) {
            cerr << "Module not connected (check USB cable)"<<endl;
            return 1;
        }
    }

    // sample code driving MAX7219 7-segment display driver
    // such as SPI7SEGDISP8.56 from www.embedded-lab.com
    spiPort->set_spiMode("250000,2,msb");
    spiPort->set_ssPolarity(Y_SSPOLARITY_ACTIVE_LOW);
    spiPort->set_protocol("Frame:5ms");
    spiPort->reset();
    cout << "****************************" << endl;
    cout << "* make sure voltage levels *" << endl;
    cout << "* are properly configured  *" << endl;
    cout << "****************************" << endl;

    spiPort->writeHex("0c01"); // Exit from shutdown state
    spiPort->writeHex("09ff"); // Enable BCD for all digits
    spiPort->writeHex("0b07"); // Enable digits 0-7 (=8 in total)
    spiPort->writeHex("0a0a"); // Set medium brightness
    for(int i = 1; i <= 8; i++) {
        std::vector<int> bytes(2);
        bytes.at(0) = i;          // digit position
        bytes.at(1) = value % 10; // digit value
        spiPort->writeArray(bytes);
        value = value / 10;
    }

    yFreeAPI();
    return 0;
}
 

11.2. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

#include <iostream>
#include <stdlib.h>

#include "yocto_api.h"

using namespace std;

static void usage(const char *exe)
{
    cout << "usage: " << exe << " <serial or logical name> [ON/OFF]" << endl;
    exit(1);
}


int main(int argc, const char * argv[])
{
    string      errmsg;

    // Setup the API to use local USB devices
    if(yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    if(argc < 2)
        usage(argv[0]);

    YModule *module = yFindModule(argv[1]);  // use serial or logical name
 
    if (module->isOnline()) {
        if (argc > 2) {
            if (string(argv[2]) == "ON")
                module->set_beacon(Y_BEACON_ON);
            else  
                module->set_beacon(Y_BEACON_OFF);
        }          
        cout << "serial:       " << module->get_serialNumber() << endl;
        cout << "logical name: " << module->get_logicalName() << endl;
        cout << "luminosity:   " << module->get_luminosity() << endl;
        cout << "beacon:       ";
        if (module->get_beacon()==Y_BEACON_ON)  
           cout << "ON" << endl;
        else  
           cout << "OFF" << endl;
        cout << "upTime:       " << module->get_upTime()/1000 << " sec" << endl;
        cout << "USB current:  " << module->get_usbCurrent() << " mA" << endl;
        cout << "Logs:"<< endl << module->get_lastLogs() << endl;
    } else {
        cout << argv[1] << " not connected (check identification and USB cable)"
             << endl;
    }
    return 0;
}
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

#include <iostream>
#include <stdlib.h>

#include "yocto_api.h"

using namespace std;

static void usage(const char *exe)
{
    cerr << "usage: " << exe << " <serial> <newLogicalName>" << endl;
    exit(1);
}

int main(int argc, const char * argv[])
{
    string      errmsg;

    // Setup the API to use local USB devices
    if(yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    if(argc < 2)
        usage(argv[0]);

    YModule *module = yFindModule(argv[1]);  // use serial or logical name
 
    if (module->isOnline()) {
        if (argc >= 3){
            string newname =  argv[2];
            if (!yCheckLogicalName(newname)){
                cerr << "Invalid name (" << newname << ")" << endl;
                usage(argv[0]);
            }
            module->set_logicalName(newname);
            module->saveToFlash();
        }
        cout << "Current name: " << module->get_logicalName() << endl;
    } else {
        cout << argv[1] << " not connected (check identification and USB cable)"
             << endl;
    }
    return 0;
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

#include <iostream>

#include "yocto_api.h"

using namespace std;

int main(int argc, const char * argv[])
{
    string      errmsg;

    // Setup the API to use local USB devices
    if(YAPI::RegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    cout << "Device list: " << endl;

    YModule *module = YModule::FirstModule();
    while (module != NULL) {
        cout << module->get_serialNumber() << " ";
        cout << module->get_productName()  << endl;
        module = module->nextModule();
    }
    return 0;
}
 

11.3. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

11.4. Integration variants for the C++ Yoctopuce library

Depending on your needs and on your preferences, you can integrate the library into your projects in several distinct manners. This section explains how to implement the different options.

Integration in source format

Integrating all the sources of the library into your projects has several advantages:

To integrate the source code, the easiest way is to simply include the Sources directory of your Yoctopuce library into your IncludePath, and to add all the files of this directory (including the sub-directory yapi) to your project.

For your project to build correctly, you need to link with your project the prerequisite system libraries, that is:

Integration as a static library

Integration of the Yoctopuce library as a static library is a simpler manner to build a small executable which uses Yoctopuce modules. You can quickly compile the program with a single command. You do not need to install a dynamic library specific to Yoctopuce, everything is in the executable.

To integrate the static Yoctopuce library to your project, you must include the Sources directory of the Yoctopuce library into your IncludePath, and add the sub-directory Binaries/... corresponding to your operating system into your libPath.

Then, for you project to build correctly, you need to link with your project the Yoctopuce library and the prerequisite system libraries:

Note, under Linux, if you wish to compile in command line with GCC, it is generally advisable to link system libraries as dynamic libraries, rather than as static ones. To mix static and dynamic libraries on the same command line, you must pass the following arguments:

gcc (...) -Wl,-Bstatic -lyocto-static -Wl,-Bdynamic -lm -lpthread -lusb-1.0 -lstdc++

Integration as a dynamic library

Integration of the Yoctopuce library as a dynamic library allows you to produce an executable smaller than with the two previous methods, and to possibly update this library, if a patch reveals itself necessary, without needing to recompile the source code of the application. On the other hand, it is an integration mode which systematically requires you to copy the dynamic library on the target machine where the application will run (yocto.dll for Windows, libyocto.so.1.0.1 for Mac OS X and Linux).

To integrate the dynamic Yoctopuce library to your project, you must include the Sources directory of the Yoctopuce library into your IncludePath, and add the sub-directory Binaries/... corresponding to your operating system into your LibPath.

Then, for you project to build correctly, you need to link with your project the dynamic Yoctopuce library and the prerequisite system libraries:

With GCC, the command line to compile is simply:

gcc (...) -lyocto -lm -lpthread -lusb-1.0 -lstdc++

12. Using Yocto-SPI with Objective-C

Objective-C is language of choice for programming on Mac OS X, due to its integration with the Cocoa framework. In order to use the Objective-C library, you need XCode version 4.2 (earlier versions will not work), available freely when you run Lion. If you are still under Snow Leopard, you need to be registered as Apple developer to be able to download XCode 4.2. The Yoctopuce library is ARC compatible. You can therefore implement your projects either using the traditional retain / release method, or using the Automatic Reference Counting.

Yoctopuce Objective-C libraries25 are integrally provided as source files. A section of the low-level library is written in pure C, but you should not need to interact directly with it: everything was done to ensure the simplest possible interaction from Objective-C.

You will soon notice that the Objective-C API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface. You can find on Yoctopuce blog a detailed example26 with video shots showing how to integrate the library into your projects.

12.1. Control of the SpiPort function

Launch Xcode 4.2 and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library.

#import <Foundation/Foundation.h>
#import "yocto_api.h"
#import "yocto_spiport.h"


static void usage(void)
{
    NSLog(@"usage: demo <serial_number> <value>");
    NSLog(@"       demo <logical_name>  <value>");
    NSLog(@"       demo any <value> (use any discovered device)");
    exit(1);
}


int main(int argc, const char * argv[])
{
    NSError *error;
   
    if (argc < 3) {
        usage();
    }
   
    @autoreleasepool{
        // Setup the API to use local USB devices
        if([YAPI RegisterHub:@"usb": &error] != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@", [error localizedDescription]);
            return 1;
        }
        NSString *target = [NSString stringWithUTF8String:argv[1]];
       
        if ([target isEqualToString:@"any"]) {
            YSpiPort *spiPort = [YSpiPort FirstSpiPort];
            if (spiPort==NULL) {
                NSLog(@"No module connected (check USB cable)");
                return 1;
            }
            target = [[spiPort module] serialNumber];
        }
       
        YSpiPort *spiPort = [YSpiPort FindSpiPort:
                                [target stringByAppendingString:@".spiPort"]];
       
        int value = (int) atol(argv[2]);
       
        if ([spiPort isOnline]) {
            [spiPort set_spiMode:@"250000,2,msb"];
            [spiPort set_ssPolarity:Y_SSPOLARITY_ACTIVE_LOW];
            [spiPort set_protocol:@"Frame:5ms"];
            [spiPort reset];
            NSLog(@"****************************");
            NSLog(@"* make sure voltage levels *");
            NSLog(@"* are properly configured  *");
            NSLog(@"****************************");
           
            [spiPort writeHex:@"0c01"]; // Exit from shutdown state
            [spiPort writeHex:@"09ff"]; // Enable BCD for all digits
            [spiPort writeHex:@"0b07"]; // Enable digits 0-7 (=8 in total)
            [spiPort writeHex:@"0a0a"]; // Set medium brightness
            for(int i = 1; i <= 8; i++) {
                NSNumber *position = [NSNumber numberWithLong:i];
                NSNumber *digit = [NSNumber numberWithInt:value % 10];
                [spiPort writeArray: [NSMutableArray arrayWithObjects:position, digit, nil]];
                value = value / 10;
            }
        } else {
            NSLog(@"Module not connected (check identification and USB cable)\n");
        }
    }
    return 0;
}
 

There are only a few really important lines in this example. We will look at them in details.

yocto_api.h et yocto_spiport.h

These two import files provide access to the functions allowing you to manage Yoctopuce modules. yocto_api.h must always be used, yocto_spiport.h is necessary to manage modules containing a SPI port, such as Yocto-SPI.

[YAPI RegisterHub]

The [YAPI RegisterHub] function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter @"usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

[SpiPort FindSpiPort]

The [SpiPort FindSpiPort] function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


YSpiPort *spiport = [SpiPort FindSpiPort:@"YSPIMK01-123456.spiPort"];
YSpiPort *spiport = [SpiPort FindSpiPort:@"YSPIMK01-123456.MyFunction"];
YSpiPort *spiport = [SpiPort FindSpiPort:@"MyModule.spiPort"];
YSpiPort *spiport = [SpiPort FindSpiPort:@"MyModule.MyFunction"];
YSpiPort *spiport = [SpiPort FindSpiPort:@"MyFunction"];

[SpiPort FindSpiPort] returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline method of the object returned by [SpiPort FindSpiPort] allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by YSpiPort.FindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by YSpiPort.FindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

12.2. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

#import <Foundation/Foundation.h>
#import "yocto_api.h"

static void usage(const char *exe)
{
    NSLog(@"usage: %s <serial or logical name> [ON/OFF]\n",exe);
    exit(1);
}


int main (int argc, const char * argv[])
{
    NSError *error;
   
    @autoreleasepool {
        // Setup the API to use local USB devices
        if([YAPI RegisterHub:@"usb": &error] != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@", [error localizedDescription]);
            return 1;
        }
        if(argc < 2)
            usage(argv[0]);
        NSString *serial_or_name =[NSString stringWithUTF8String:argv[1]];
        // use serial or logical name
        YModule *module = [YModule FindModule:serial_or_name];  
        if ([module isOnline]) {
            if (argc > 2) {
                if (strcmp(argv[2], "ON")==0)
                    [module setBeacon:Y_BEACON_ON];
                else  
                    [module setBeacon:Y_BEACON_OFF];
            }        
            NSLog(@"serial:       %@\n", [module serialNumber]);
            NSLog(@"logical name: %@\n", [module logicalName]);
            NSLog(@"luminosity:   %d\n", [module luminosity]);
            NSLog(@"beacon:       ");
            if ([module beacon] == Y_BEACON_ON)
               NSLog(@"ON\n");
            else  
               NSLog(@"OFF\n");
            NSLog(@"upTime:       %ld sec\n", [module upTime]/1000);
            NSLog(@"USB current:  %d mA\n",  [module usbCurrent]);
            NSLog(@"logs:  %@\n",  [module get_lastLogs]);
        } else {
            NSLog(@"%@ not connected (check identification and USB cable)\n",
                serial_or_name);
        }
    }
    return 0;
}
 

Each property xxx of the module can be read thanks to a method of type get_xxxx, and properties which are not read-only can be modified with the help of the set_xxx: method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx: function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash method. The short example below allows you to modify the logical name of a module.

#import <Foundation/Foundation.h>
#import "yocto_api.h"

static void usage(const char *exe)
{
    NSLog(@"usage: %s <serial> <newLogicalName>\n",exe);
    exit(1);
}


int main (int argc, const char * argv[])
{
    NSError *error;

    @autoreleasepool {
        // Setup the API to use local USB devices
        if([YAPI RegisterHub:@"usb" :&error] != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@", [error localizedDescription]);
            return 1;
        }

        if(argc < 2)
            usage(argv[0]);

        NSString *serial_or_name =[NSString stringWithUTF8String:argv[1]];
        // use serial or logical name
        YModule *module = [YModule FindModule:serial_or_name];
     
        if (module.isOnline) {
            if (argc >= 3){
                NSString *newname =  [NSString stringWithUTF8String:argv[2]];
                if (![YAPI CheckLogicalName:newname]){
                    NSLog(@"Invalid name (%@)\n", newname);
                    usage(argv[0]);
                }
                module.logicalName = newname;
                [module saveToFlash];
            }
            NSLog(@"Current name: %@\n", module.logicalName);
        } else {
            NSLog(@"%@ not connected (check identification and USB cable)\n",
                serial_or_name);
        }
    }
    return 0;
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

#import <Foundation/Foundation.h>
#import "yocto_api.h"

int main (int argc, const char * argv[])
{
    NSError *error;
   
    @autoreleasepool {
        // Setup the API to use local USB devices
        if([YAPI RegisterHub:@"usb" :&error] != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@\n", [error localizedDescription]);
            return 1;
        }

        NSLog(@"Device list:\n");

        YModule *module = [YModule FirstModule];
        while (module != nil) {
            NSLog(@"%@ %@",module.serialNumber, module.productName);
            module = [module nextModule];
        }
    }
    return 0;
}
 

12.3. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

13. Using Yocto-SPI with Visual Basic .NET

VisualBasic has long been the most favored entrance path to the Microsoft world. Therefore, we had to provide our library for this language, even if the new trend is shifting to C#. All the examples and the project models are tested with Microsoft VisualBasic 2010 Express, freely available on the Microsoft web site27.

13.1. Installation

Download the Visual Basic Yoctopuce library from the Yoctopuce web site28. There is no setup program, simply copy the content of the zip file into the directory of your choice. You mostly need the content of the Sources directory. The other directories contain the documentation and a few sample programs. All sample projects are Visual Basic 2010, projects, if you are using a previous version, you may have to recreate the projects structure from scratch.

13.2. Using the Yoctopuce API in a Visual Basic project

The Visual Basic.NET Yoctopuce library is composed of a DLL and of source files in Visual Basic. The DLL is not a .NET DLL, but a classic DLL, written in C, which manages the low level communications with the modules29. The source files in Visual Basic manage the high level part of the API. Therefore, your need both this DLL and the .vb files of the sources directory to create a project managing Yoctopuce modules.

Configuring a Visual Basic project

The following indications are provided for Visual Studio Express 2010, but the process is similar for other versions. Start by creating your project. Then, on the Solution Explorer panel, right click on your project, and select "Add" and then "Add an existing item".

A file selection window opens. Select the yocto_api.vb file and the files corresponding to the functions of the Yoctopuce modules that your project is going to manage. If in doubt, select all the files.

You then have the choice between simply adding these files to your project, or to add them as links (the Add button is in fact a scroll-down menu). In the first case, Visual Studio copies the selected files into your project. In the second case, Visual Studio simply keeps a link on the original files. We recommend you to use links, which makes updates of the library much easier.

Then add in the same manner the yapi.dll DLL, located in the Sources/dll directory30. Then, from the Solution Explorer window, right click on the DLL, select Properties and in the Properties panel, set the Copy to output folder to always. You are now ready to use your Yoctopuce modules from Visual Studio.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

13.3. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a Visual Basic code snipplet to use the SpiPort function.


[...]
Dim errmsg As String errmsg
Dim spiport As YSpiPort
 
REM Get access to your device, connected locally on USB for instance
yRegisterHub("usb", errmsg)
spiport = yFindSpiPort("YSPIMK01-123456.spiPort")

REM Hot-plug is easy: just check that the device is online
If (spiport.isOnline()) Then
   REM Use spiport.set_spiMode(), ...
End If

Let's look at these lines in more details.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindSpiPort

The yFindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport = yFindSpiPort("YSPIMK01-123456.spiPort")
spiport = yFindSpiPort("YSPIMK01-123456.MyFunction")
spiport = yFindSpiPort("MyModule.spiPort")
spiport = yFindSpiPort("MyModule.MyFunction")
spiport = yFindSpiPort("MyFunction")

yFindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by yFindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by yFindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by yFindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Launch Microsoft VisualBasic and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

Module Module1

  Private Sub Usage()
    Dim execname = System.AppDomain.CurrentDomain.FriendlyName
    Console.WriteLine("Usage")
    Console.WriteLine(execname + " <serial_number>  <frequency> <dutyCycle>")
    Console.WriteLine(execname + " <logical_name> <frequency> <dutyCycle>")
    Console.WriteLine(execname + " any  <frequency> <dutyCycle>   (use any discovered device)")
    Console.WriteLine("     <frequency>: integer between 1Hz and 1000000Hz")
    Console.WriteLine("     <dutyCycle>: floating point number between 0.0 and 100.0")
    System.Threading.Thread.Sleep(2500)
    End
  End Sub


  Sub Main()
    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim errmsg As String = ""
    Dim target As String
    Dim value As Integer
    Dim spiPort As YSpiPort
    Dim i, digit As Integer

    If argv.Length < 2 Then Usage()

    target = argv(1)
    value = CInt(argv(2))

    REM Setup the API to use local USB devices
    If (yRegisterHub("usb", errmsg) <> YAPI_SUCCESS) Then
      Console.WriteLine("RegisterHub error: " + errmsg)
      End
    End If

    If target = "any" Then
      spiPort = yFirstSpiPort()
      If spiPort Is Nothing Then
        Console.WriteLine("No module connected (check USB cable) ")
        End
      End If
      target = spiPort.get_module().get_serialNumber()
    End If
    spiPort = yFindSpiPort(target + ".spiPort")

    If (spiPort.isOnline()) Then
      spiPort.set_spiMode("250000,2,msb")
      spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW)
      spiPort.set_protocol("Frame:5ms")
      spiPort.reset()
      Console.WriteLine("****************************")
      Console.WriteLine("* make sure voltage levels *")
      Console.WriteLine("* are properly configured  *")
      Console.WriteLine("****************************")

      spiPort.writeHex("0c01") REM -- Exit from shutdown state
      spiPort.writeHex("09ff") REM -- Enable BCD for all digits
      spiPort.writeHex("0b07") REM -- Enable digits 0-7 (=8 in total)
      spiPort.writeHex("0a0a") REM -- Set medium brightness
      For i = 1 To 8
        digit = value Mod 10
        spiPort.writeArray(New List(Of Integer)(New Integer() {i, digit}))
        value = value \ 10
      Next
    Else
      Console.WriteLine("Module not connected (check identification and USB cable)")
    End If
    YAPI.FreeAPI()
  End Sub

End Module

13.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.


Imports System.IO
Imports System.Environment

Module Module1

  Sub usage()
    Console.WriteLine("usage: demo <serial or logical name> [ON/OFF]")  
    End
  End Sub

  Sub Main()
    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim errmsg As String = ""
    Dim m As ymodule

    If (yRegisterHub("usb", errmsg) <> YAPI_SUCCESS) Then
      Console.WriteLine("RegisterHub error:" + errmsg)
      End
    End If

    If argv.Length < 2 Then usage()

    m = yFindModule(argv(1)) REM use serial or logical name

    If (m.isOnline()) Then
      If argv.Length > 2 Then
        If argv(2) = "ON" Then m.set_beacon(Y_BEACON_ON)
        If argv(2) = "OFF" Then m.set_beacon(Y_BEACON_OFF)
      End If
      Console.WriteLine("serial:       " + m.get_serialNumber())
      Console.WriteLine("logical name: " + m.get_logicalName())
      Console.WriteLine("luminosity:   " + Str(m.get_luminosity()))
      Console.Write("beacon:       ")
      If (m.get_beacon() = Y_BEACON_ON) Then
        Console.WriteLine("ON")
      Else
        Console.WriteLine("OFF")
      End If
      Console.WriteLine("upTime:       " + Str(m.get_upTime() / 1000) + " sec")
      Console.WriteLine("USB current:  " + Str(m.get_usbCurrent()) + " mA")
      Console.WriteLine("Logs:")
      Console.WriteLine(m.get_lastLogs())
    Else
      Console.WriteLine(argv(1) + " not connected (check identification and USB cable)")
    End If



  End Sub

End Module
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

Module Module1


  Sub usage()

    Console.WriteLine("usage: demo <serial or logical name> <new logical name>")
    End
  End Sub

  Sub Main()
    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim errmsg As String = ""
    Dim newname As String
    Dim m As YModule

    If (argv.Length <> 3) Then usage()

    REM Setup the API to use local USB devices
    If yRegisterHub("usb", errmsg) <> YAPI_SUCCESS Then
      Console.WriteLine("RegisterHub error: " + errmsg)
      End
    End If

    m = yFindModule(argv(1)) REM use serial or logical name
    If m.isOnline() Then

      newname = argv(2)
      If (Not yCheckLogicalName(newname)) Then
        Console.WriteLine("Invalid name (" + newname + ")")
        End
      End If
      m.set_logicalName(newname)
      m.saveToFlash() REM do not forget this

      Console.Write("Module: serial= " + m.get_serialNumber)
      Console.Write(" / name= " + m.get_logicalName())
    Else
      Console.Write("not connected (check identification and USB cable")
    End If

  End Sub

End Module
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not Nothing. Below a short example listing the connected modules.

Module Module1

  Sub Main()
    Dim M As ymodule
    Dim errmsg As String = ""

    REM Setup the API to use local USB devices
    If yRegisterHub("usb", errmsg) <> YAPI_SUCCESS Then
      Console.WriteLine("RegisterHub error: " + errmsg)
      End
    End If

    Console.WriteLine("Device list")
    M = yFirstModule()
    While M IsNot Nothing
      Console.WriteLine(M.get_serialNumber() + " (" + M.get_productName() + ")")
      M = M.nextModule()
    End While

  End Sub

    End Module
 

13.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

14. Using Yocto-SPI with C#

C# (pronounced C-Sharp) is an object-oriented programming language promoted by Microsoft, it is somewhat similar to Java. Like Visual-Basic and Delphi, it allows you to create Windows applications quite easily. All the examples and the project models are tested with Microsoft C# 2010 Express, freely available on the Microsoft web site31.

14.1. Installation

Download the Visual C# Yoctopuce library from the Yoctopuce web site32. There is no setup program, simply copy the content of the zip file into the directory of your choice. You mostly need the content of the Sources directory. The other directories contain the documentation and a few sample programs. All sample projects are Visual C# 2010, projects, if you are using a previous version, you may have to recreate the projects structure from scratch.

14.2. Using the Yoctopuce API in a Visual C# project

The Visual C#.NET Yoctopuce library is composed of a DLL and of source files in Visual C#. The DLL is not a .NET DLL, but a classic DLL, written in C, which manages the low level communications with the modules33. The source files in Visual C# manage the high level part of the API. Therefore, your need both this DLL and the .cs files of the sources directory to create a project managing Yoctopuce modules.

Configuring a Visual C# project

The following indications are provided for Visual Studio Express 2010, but the process is similar for other versions. Start by creating your project. Then, on the Solution Explorer panel, right click on your project, and select "Add" and then "Add an existing item".

A file selection window opens. Select the yocto_api.cs file and the files corresponding to the functions of the Yoctopuce modules that your project is going to manage. If in doubt, select all the files.

You then have the choice between simply adding these files to your project, or to add them as links (the Add button is in fact a scroll-down menu). In the first case, Visual Studio copies the selected files into your project. In the second case, Visual Studio simply keeps a link on the original files. We recommend you to use links, which makes updates of the library much easier.

Then add in the same manner the yapi.dll DLL, located in the Sources/dll directory34. Then, from the Solution Explorer window, right click on the DLL, select Properties and in the Properties panel, set the Copy to output folder to always. You are now ready to use your Yoctopuce modules from Visual Studio.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

14.3. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a C# code snipplet to use the SpiPort function.


[...]
string errmsg ="";
YSpiPort spiport;
 
// Get access to your device, connected locally on USB for instance
YAPI.RegisterHub("usb", errmsg);
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort");

// Hot-plug is easy: just check that the device is online
if (spiport.isOnline())
 {  // Use spiport.set_spiMode(); ...
 }

Let's look at these lines in more details.

YAPI.RegisterHub

The YAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI.SUCCESS and errmsg contains the error message.

YSpiPort.FindSpiPort

The YSpiPort.FindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort");
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.MyFunction");
spiport = YSpiPort.FindSpiPort("MyModule.spiPort");
spiport = YSpiPort.FindSpiPort("MyModule.MyFunction");
spiport = YSpiPort.FindSpiPort("MyFunction");

YSpiPort.FindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by YSpiPort.FindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by YSpiPort.FindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by YSpiPort.FindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Launch Microsoft Visual C# and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void usage()
        {
            string execname = System.AppDomain.CurrentDomain.FriendlyName;
            Console.WriteLine("Usage");
            Console.WriteLine(execname + " <serial_number> <value>");
            Console.WriteLine(execname + " <logical_name>  <value>");
            Console.WriteLine(execname + " any  <value>   (use any discovered device)");
            System.Threading.Thread.Sleep(2500);
            Environment.Exit(0);
        }

        static void Main(string[] args)
        {
            string errmsg = "";
            string target;
            int value;
            YSpiPort spiPort;

            if (args.Length < 2) usage();
            target = args[0].ToUpper();
            value = Convert.ToInt32(args[1]);

            if (YAPI.RegisterHub("usb", ref errmsg) != YAPI.SUCCESS)
            {
                Console.WriteLine("RegisterHub error: " + errmsg);
                Environment.Exit(0);
            }

            if (target == "ANY")
            {
                spiPort = YSpiPort.FirstSpiPort();
                if (spiPort == null)
                {
                    Console.WriteLine("No module connected (check USB cable) ");
                    Environment.Exit(0);
                }
                target = spiPort.get_module().get_serialNumber();
            }

            spiPort = YSpiPort.FindSpiPort(target + ".spiPort");
            if (spiPort.isOnline())
            {
                spiPort.set_spiMode("250000,2,msb");
                spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW);
                spiPort.set_protocol("Frame:5ms");
                spiPort.reset();
                Console.WriteLine("****************************");
                Console.WriteLine("* make sure voltage levels *");
                Console.WriteLine("* are properly configured  *");
                Console.WriteLine("****************************");

                spiPort.writeHex("0c01"); // Exit from shutdown state
                spiPort.writeHex("09ff"); // Enable BCD for all digits
                spiPort.writeHex("0b07"); // Enable digits 0-7 (=8 in total)
                spiPort.writeHex("0a0a"); // Set medium brightness
                for(int i = 1; i <= 8; i++) {
                    int digit = value % 10; // digit value
                    spiPort.writeArray(new List<int> { i, digit });
                    value = value / 10;
                }
            }
            else
                Console.WriteLine("Module not connected (check identification and USB cable)");

            YAPI.FreeAPI();
        }
    }
}
 

14.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


namespace ConsoleApplication1
{
  class Program
  {
    static void usage()
    { string execname = System.AppDomain.CurrentDomain.FriendlyName;
      Console.WriteLine("Usage:");
      Console.WriteLine(execname+" <serial or logical name> [ON/OFF]");
      System.Threading.Thread.Sleep(2500);
      Environment.Exit(0);
    }

    static void Main(string[] args)
    {
      YModule m;
      string errmsg = "";

      if (YAPI.RegisterHub("usb", ref errmsg) !=  YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

     
      if (args.Length < 1)  usage();

      m = YModule.FindModule(args[0]); // use serial or logical name

      if (m.isOnline())
      {
        if (args.Length >= 2)
        {
          if (args[1].ToUpper() == "ON") { m.set_beacon(YModule.BEACON_ON); }
          if (args[1].ToUpper() == "OFF") { m.set_beacon(YModule.BEACON_OFF); }
        }
     
        Console.WriteLine("serial:       " + m.get_serialNumber());
        Console.WriteLine("logical name: " + m.get_logicalName());
        Console.WriteLine("luminosity:   " + m.get_luminosity().ToString());
        Console.Write("beacon:       ");
        if (m.get_beacon() == YModule.BEACON_ON)
          Console.WriteLine("ON");
        else
          Console.WriteLine("OFF");
        Console.WriteLine("upTime:       " + (m.get_upTime() / 1000 ).ToString()+ " sec");
        Console.WriteLine("USB current:  " + m.get_usbCurrent().ToString() + " mA");
        Console.WriteLine("Logs:\r\n"+ m.get_lastLogs());

      }
    else
      Console.WriteLine(args[0] + " not connected (check identification and USB cable)");
   
   }
  }
}
 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
  class Program
  {
    static void usage()
    { string execname = System.AppDomain.CurrentDomain.FriendlyName;
      Console.WriteLine("Usage:");
      Console.WriteLine("usage: demo <serial or logical name> <new logical name>");
      System.Threading.Thread.Sleep(2500);
      Environment.Exit(0);
    }

    static void Main(string[] args)
    {
      YModule m;
      string errmsg = "";
      string newname;

      if (args.Length != 2) usage();

      if (YAPI.RegisterHub("usb", ref errmsg) !=  YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

      m = YModule.FindModule(args[0]); // use serial or logical name

      if (m.isOnline())
      {
        newname = args[1];
        if (!YAPI.CheckLogicalName(newname))
        {
          Console.WriteLine("Invalid name (" + newname + ")");
          Environment.Exit(0);
        }

        m.set_logicalName(newname);
        m.saveToFlash(); // do not forget this

        Console.Write("Module: serial= " + m.get_serialNumber());
        Console.WriteLine(" / name= " + m.get_logicalName());
      }
      else
        Console.Write("not connected (check identification and USB cable");
    }
  }
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
  class Program
  {
    static void Main(string[] args)
    {
      YModule m;
      string errmsg = "";

      if (YAPI.RegisterHub("usb", ref errmsg) !=  YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

      Console.WriteLine("Device list");
      m = YModule.FirstModule();
      while (m!=null)
      { Console.WriteLine(m.get_serialNumber() + " (" + m.get_productName() + ")");
       m = m.nextModule();
      }

    }
  }
}
 

14.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

15. Using Yocto-SPI with Delphi

Delphi is a descendent of Turbo-Pascal. Originally, Delphi was produced by Borland, Embarcadero now edits it. The strength of this language resides in its ease of use, as anyone with some notions of the Pascal language can develop a Windows application in next to no time. Its only disadvantage is to cost something35.

Delphi libraries are provided not as VCL components, but directly as source files. These files are compatible with most Delphi versions. 36

To keep them simple, all the examples provided in this documentation are console applications. Obviously, the libraries work in a strictly identical way with VCL applications.

You will soon notice that the Delphi API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.

15.1. Preparation

Go to the Yoctopuce web site and download the Yoctopuce Delphi libraries37. Uncompress everything in a directory of your choice, add the subdirectory sources in the list of directories of Delphi libraries.38

By default, the Yoctopuce Delphi library uses the yapi.dll DLL, all the applications you will create with Delphi must have access to this DLL. The simplest way to ensure this is to make sure yapi.dll is located in the same directory as the executable file of your application.

15.2. Control of the SpiPort function

Launch your Delphi environment, copy the yapi.dll DLL in a directory, create a new console application in the same directory, and copy-paste the piece of code below:

program helloworld;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api,
  yocto_spiport;

procedure usage();
  var
    execname:string;
  begin
    execname := ExtractFileName(paramstr(0));
    WriteLn('Usage:');
    WriteLn(execname + '<serial_number> <value>');
    WriteLn(execname + '<logical_name>  <value>');
    WriteLn(execname + 'any  <value>   (use any discovered device)');
    //sleep(2500);
    halt;
  end;

var
 errmsg,target : string;
 value,i : integer;
 m : TYModule;
 spiPort : TYSpiPort;
 bytes : TLongIntArray;

begin
  if (paramcount<2) then usage();
  target := UpperCase(paramstr(1));
  value  := StrToInt(paramstr(2));

  if (YRegisterHub('usb', errmsg) <> YAPI_SUCCESS)  then
    begin
      writeln('RegisterHub error: ' + errmsg);
      halt;
    end;

  if (target='ANY') then
    begin
      spiPort := YFirstSpiPort();
      if (spiPort = nil) then
       begin
         writeln('No module connected (check USB cable)');
         halt;
       end;
      m := spiPort.get_module();
      target := m.get_serialNumber();
     end;

  Writeln('using ' + target);
  spiPort := YFindSpiPort(target + '.spiPort');

  if (spiPort.isOnline()) then
    begin
      spiPort.set_spiMode('250000,2,msb');
      spiPort.set_ssPolarity(Y_SSPOLARITY_ACTIVE_LOW);
      spiPort.set_protocol('Frame:5ms');
      spiPort.reset();
      writeln('****************************');
      writeln('* make sure voltage levels *');
      writeln('* are properly configured  *');
      writeln('****************************');
     
      spiPort.writeHex('0c01'); // Exit from shutdown state
      spiPort.writeHex('09ff'); // Enable BCD for all digits
      spiPort.writeHex('0b07'); // Enable digits 0-7 (=8 in total)
      spiPort.writeHex('0a0a'); // Set medium brightness
      setLength(bytes,2);
      for i := 1 to 8 do
        begin
          bytes[0] := i;          // digit position
          bytes[1] := value mod 10; // digit value
          spiPort.writeArray(bytes);
          value := value div 10;
        end
    end
  else writeln('Module not connected (check identification and USB cable)');

  yFreeAPI();
end.
 

There are only a few really important lines in this sample example. We will look at them in details.

yocto_api and yocto_spiport

These two units provide access to the functions allowing you to manage Yoctopuce modules. yocto_api must always be used, yocto_spiport is necessary to manage modules containing a SPI port, such as Yocto-SPI.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and specifies where the modules should be looked for. When used with the parameter 'usb', it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindSpiPort

The yFindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can also use logical names, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport := yFindSpiPort("YSPIMK01-123456.spiPort");
spiport := yFindSpiPort("YSPIMK01-123456.MyFunction");
spiport := yFindSpiPort("MyModule.spiPort");
spiport := yFindSpiPort("MyModule.MyFunction");
spiport := yFindSpiPort("MyFunction");

yFindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by yFindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by yFindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by yFindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

15.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

program modulecontrol;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api;

const
  serial = 'YSPIMK01-123456'; // use serial number or logical name

procedure refresh(module:Tymodule) ;
  begin
    if (module.isOnline())  then
     begin
       Writeln('');
       Writeln('Serial       : ' + module.get_serialNumber());
       Writeln('Logical name : ' + module.get_logicalName());
       Writeln('Luminosity   : ' + intToStr(module.get_luminosity()));
       Write('Beacon    :');
       if  (module.get_beacon()=Y_BEACON_ON) then Writeln('on')
                                             else Writeln('off');
       Writeln('uptime       : ' + intToStr(module.get_upTime() div 1000)+'s');
       Writeln('USB current  : ' + intToStr(module.get_usbCurrent())+'mA');
       Writeln('Logs         : ');
       Writeln(module.get_lastlogs());
       Writeln('');
       Writeln('r : refresh / b:beacon ON / space : beacon off');
     end
    else Writeln('Module not connected (check identification and USB cable)');
  end;


procedure beacon(module:Tymodule;state:integer);
  begin
    module.set_beacon(state);
    refresh(module);
  end;

var
  module : TYModule;
  c      : char;
  errmsg : string;

begin
  // Setup the API to use local USB devices
  if yRegisterHub('usb', errmsg)<>YAPI_SUCCESS then
  begin
    Write('RegisterHub error: '+errmsg);
    exit;
  end;

  module := yFindModule(serial);
  refresh(module);

  repeat
    read(c);
    case c of
     'r': refresh(module);
     'b': beacon(module,Y_BEACON_ON);
     ' ': beacon(module,Y_BEACON_OFF);
    end;
  until  c = 'x';
end.

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

program savesettings;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api;

const
  serial = 'YSPIMK01-123456'; // use serial number or logical name

var
  module  : TYModule;
  errmsg  : string;
  newname : string;
 
begin
  // Setup the API to use local USB devices
  if yRegisterHub('usb', errmsg)<>YAPI_SUCCESS then
  begin
    Write('RegisterHub error: '+errmsg);
    exit;
  end;

  module := yFindModule(serial);
  if (not(module.isOnline)) then
   begin
     writeln('Module not connected (check identification and USB cable)');
     exit;
   end;

  Writeln('Current logical name : '+module.get_logicalName());
  Write('Enter new name : ');
  Readln(newname);
  if (not(yCheckLogicalName(newname))) then
   begin
     Writeln('invalid logical name');
     exit;
   end;
  module.set_logicalName(newname);
  module.saveToFlash();
 
  Writeln('logical name is now : '+module.get_logicalName());
end.
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not nil. Below a short example listing the connected modules.

program inventory;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api;

var
  module : TYModule;
  errmsg : string;

begin
  // Setup the API to use local USB devices
  if yRegisterHub('usb', errmsg)<>YAPI_SUCCESS then
  begin
    Write('RegisterHub error: '+errmsg);
    exit;
  end;

  Writeln('Device list');

  module := yFirstModule();
  while module<>nil  do
   begin
     Writeln( module.get_serialNumber()+' ('+module.get_productName()+')');
     module := module.nextModule();
   end;

end.

15.4. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

16. Using the Yocto-SPI with Python

Python is an interpreted object oriented language developed by Guido van Rossum. Among its advantages is the fact that it is free, and the fact that it is available for most platforms, Windows as well as UNIX. It is an ideal language to write small scripts on a napkin. The Yoctopuce library is compatible with Python 2.6+ and 3+. It works under Windows, Mac OS X, and Linux, Intel as well as ARM. The library was tested with Python 2.6 and Python 3.2. Python interpreters are available on the Python web site39.

16.1. Source files

The Yoctopuce library classes40 for Python that you will use are provided as source files. Copy all the content of the Sources directory in the directory of your choice and add this directory to the PYTHONPATH environment variable. If you use an IDE to program in Python, refer to its documentation to configure it so that it automatically finds the API source files.

16.2. Dynamic library

A section of the low-level library is written in C, but you should not need to interact directly with it: it is provided as a DLL under Windows, as a .so files under UNIX, and as a .dylib file under Mac OS X. Everything was done to ensure the simplest possible interaction from Python: the distinct versions of the dynamic library corresponding to the distinct operating systems and architectures are stored in the cdll directory. The API automatically loads the correct file during its initialization. You should not have to worry about it.

If you ever need to recompile the dynamic library, its complete source code is located in the Yoctopuce C++ library.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

16.3. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a Python code snipplet to use the SpiPort function.


[...]

errmsg=YRefParam()
#Get access to your device, connected locally on USB for instance
YAPI.RegisterHub("usb",errmsg)
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort")

# Hot-plug is easy: just check that the device is online
if spiport.isOnline():
    #Use spiport.set_spiMode()
    ...
   
[...]    

Let's look at these lines in more details.

YAPI.RegisterHub

The yAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI.SUCCESS and errmsg contains the error message.

YSpiPort.FindSpiPort

The YSpiPort.FindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort")
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.MyFunction")
spiport = YSpiPort.FindSpiPort("MyModule.spiPort")
spiport = YSpiPort.FindSpiPort("MyModule.MyFunction")
spiport = YSpiPort.FindSpiPort("MyFunction")

YSpiPort.FindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by YSpiPort.FindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by YSpiPort.FindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by YSpiPort.FindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Launch Python and open the corresponding sample script provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os, sys
sys.path.append(os.path.join("..", "..", "Sources"))
from yocto_api import *
from yocto_spiport import *

def usage():
    scriptname = os.path.basename(sys.argv[0])
    print("Usage:")
    print(scriptname + " <serial_number>  <value>")
    print(scriptname + " <logical_name>   <value>")
    print(scriptname + " any  <value>   (use any discovered device)")
    sys.exit()

def die(msg):
    sys.exit(msg + ' (check USB cable)')

if len(sys.argv) < 3:
    usage()
target = sys.argv[1].upper()
value = int(sys.argv[2])

# Setup the API to use local USB devices. You can
# use an IP address instead of 'usb' if the device
# is connected to a network.
errmsg = YRefParam()
if YAPI.RegisterHub("usb", errmsg) != YAPI.SUCCESS:
    sys.exit("init error" + errmsg.value)

if target == 'ANY':
    spiPort = YSpiPort.FirstSpiPort()
    if spiPort is None:
        sys.exit('No module connected (check cable)')
else:
    spiPort = YSpiPort.FindSpiPort(sys.argv[1] + ".spiPort")
    if not spiPort.isOnline():
        sys.exit('Module not connected')

# sample code driving MAX7219 7-segment display driver
# such as SPI7SEGDISP8.56 from www.embedded-lab.com
spiPort.set_spiMode("250000,2,msb")
spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW)
spiPort.set_protocol("Frame:5ms")
spiPort.reset()

print("****************************")
print("* make sure voltage levels *")
print("* are properly configured  *")
print("****************************")

# initialize MAX7219
spiPort.writeHex('0c01') # Exit from shutdown state
spiPort.writeHex('09ff') # Enable BCD for all digits
spiPort.writeHex('0b07') # Enable digits 0-7 (=8 in total)
spiPort.writeHex('0a0a') # Set medium brightness
for i in range(1, 9):
    digit = value % 10
    spiPort.writeArray([i, digit])
    value = int(value / 10)

YAPI.FreeAPI()
 

16.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os, sys
from yocto_api import *


def usage():
    sys.exit("usage: demo <serial or logical name> [ON/OFF]")


errmsg = YRefParam()
if YAPI.RegisterHub("usb", errmsg) != YAPI.SUCCESS:
    sys.exit("RegisterHub error: " + str(errmsg))

if len(sys.argv) < 2:
    usage()

m = YModule.FindModule(sys.argv[1])  # # use serial or logical name

if m.isOnline():
    if len(sys.argv) > 2:
        if sys.argv[2].upper() == "ON":
            m.set_beacon(YModule.BEACON_ON)
        if sys.argv[2].upper() == "OFF":
            m.set_beacon(YModule.BEACON_OFF)

    print("serial:       " + m.get_serialNumber())
    print("logical name: " + m.get_logicalName())
    print("luminosity:   " + str(m.get_luminosity()))
    if m.get_beacon() == YModule.BEACON_ON:
        print("beacon:       ON")
    else:
        print("beacon:       OFF")
    print("upTime:       " + str(m.get_upTime() / 1000) + " sec")
    print("USB current:  " + str(m.get_usbCurrent()) + " mA")
    print("logs:\n" + m.get_lastLogs())
else:
    print(sys.argv[1] + " not connected (check identification and USB cable)")



 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os, sys
from yocto_api import *


def usage():
    sys.exit("usage: demo <serial or logical name> <new logical name>")


if len(sys.argv) != 3:
    usage()

errmsg = YRefParam()
if YAPI.RegisterHub("usb", errmsg) != YAPI.SUCCESS:
    sys.exit("RegisterHub error: " + str(errmsg))

m = YModule.FindModule(sys.argv[1])  # use serial or logical name
if m.isOnline():
    newname = sys.argv[2]
    if not YAPI.CheckLogicalName(newname):
        sys.exit("Invalid name (" + newname + ")")
    m.set_logicalName(newname)
    m.saveToFlash()  # do not forget this
    print("Module: serial= " + m.get_serialNumber() + " / name= " + m.get_logicalName())
else:
    sys.exit("not connected (check identification and USB cable")

 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os,sys

from yocto_api import *

errmsg = YRefParam()

# Setup the API to use local USB devices
if YAPI.RegisterHub("usb", errmsg) != YAPI.SUCCESS:
    sys.exit("init error" + str(errmsg))

print('Device list')

module = YModule.FirstModule()
while module is not None:
    print(module.get_serialNumber() + ' (' + module.get_productName() + ')')
    module = module.nextModule()
 

16.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the YAPI.DisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

17. Using the Yocto-SPI with Java

Java is an object oriented language created by Sun Microsystem. Beside being free, its main strength is its portability. Unfortunately, this portability has an excruciating price. In Java, hardware abstraction is so high that it is almost impossible to work directly with the hardware. Therefore, the Yoctopuce API does not support native mode in regular Java. The Java API needs a Virtual Hub to communicate with Yoctopuce devices.

17.1. Getting ready

Go to the Yoctopuce web site and download the following items:

The library is available as source files as well as a jar file. Decompress the library files in a folder of your choice, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

17.2. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a Java code snippet to use the SpiPort function.


[...]

// Get access to your device, connected locally on USB for instance
YAPI.RegisterHub("127.0.0.1");
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort");

// Hot-plug is easy: just check that the device is online
if (spiport.isOnline())
{    
    // Use spiport.set_spiMode()
    [...]
}

[...]

Let us look at these lines in more details.

YAPI.RegisterHub

The yAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. The parameter is the address of the Virtual Hub able to see the devices. If the initialization does not succeed, an exception is thrown.

YSpiPort.FindSpiPort

The YSpiPort.FindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort")
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.MyFunction")
spiport = YSpiPort.FindSpiPort("MyModule.spiPort")
spiport = YSpiPort.FindSpiPort("MyModule.MyFunction")
spiport = YSpiPort.FindSpiPort("MyFunction")

YSpiPort.FindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by YSpiPort.FindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by YSpiPort.FindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by YSpiPort.FindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Launch you Java environment and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-SPI of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all the side materials needed to make it work nicely as a small demo.

import com.yoctopuce.YoctoAPI.*;

import java.util.ArrayList;

public class Demo
{

    public static void usage()
    {
        System.out.println("Usage");
        System.out.println("demo <serial_number> <value>");
        System.out.println("demo <logical_name>  <value>");
        System.out.println("demo any  <value>   (use any discovered device)");
        System.exit(1);
    }

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }

        if (args.length < 2) usage();
        String target = args[0].toUpperCase();
        int value = Integer.valueOf(args[1]);

        if (target.equals("ANY")) {
            YSpiPort tmp = YSpiPort.FirstSpiPort();
            if (tmp == null) {
                System.out.println("No module connected (check USB cable)");
                System.exit(1);
            }
            try {
                target = tmp.module().get_serialNumber();
            } catch (YAPI_Exception ex) {
                System.out.println("No module connected (check USB cable)");
                System.exit(1);
            }
        }

        YSpiPort spiPort = YSpiPort.FindSpiPort(target + ".spiPort");
        try {
            // sample code driving MAX7219 7-segment display driver
            // such as SPI7SEGDISP8.56 from www.embedded-lab.com
            spiPort.set_spiMode("250000,2,msb");
            spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW);
            spiPort.set_protocol("Frame:5ms");
            spiPort.reset();
            System.out.println("****************************");
            System.out.println("* make sure voltage levels *");
            System.out.println("* are properly configured  *");
            System.out.println("****************************");

            spiPort.writeHex("0c01"); // Exit from shutdown state
            spiPort.writeHex("09ff"); // Enable BCD for all digits
            spiPort.writeHex("0b07"); // Enable digits 0-7 (=8 in total)
            spiPort.writeHex("0a0a"); // Set medium brightness
            for (int i = 1; i <= 8; i++) {
                int digit = value % 10;
                ArrayList<Integer> dataToWrite = new ArrayList<>(2);
                dataToWrite.add(i);
                dataToWrite.add(digit);
                spiPort.writeArray(dataToWrite);
                value = value / 10;
            }
        } catch (YAPI_Exception ex) {
            System.out.println("Module not connected (check identification and USB cable)");
        }
        YAPI.FreeAPI();
    }
}
 

17.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.


import com.yoctopuce.YoctoAPI.*;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Demo {

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }
        System.out.println("usage: demo [serial or logical name] [ON/OFF]");

        YModule module;
        if (args.length == 0) {
            module = YModule.FirstModule();
            if (module == null) {
                System.out.println("No module connected (check USB cable)");
                System.exit(1);
            }
        } else {
            module = YModule.FindModule(args[0]);  // use serial or logical name
        }

        try {
            if (args.length > 1) {
                if (args[1].equalsIgnoreCase("ON")) {
                    module.setBeacon(YModule.BEACON_ON);
                } else {
                    module.setBeacon(YModule.BEACON_OFF);
                }
            }
            System.out.println("serial:       " + module.get_serialNumber());
            System.out.println("logical name: " + module.get_logicalName());
            System.out.println("luminosity:   " + module.get_luminosity());
            if (module.get_beacon() == YModule.BEACON_ON) {
                System.out.println("beacon:       ON");
            } else {
                System.out.println("beacon:       OFF");
            }
            System.out.println("upTime:       " + module.get_upTime() / 1000 + " sec");
            System.out.println("USB current:  " + module.get_usbCurrent() + " mA");
            System.out.println("logs:\n" + module.get_lastLogs());
        } catch (YAPI_Exception ex) {
            System.out.println(args[1] + " not connected (check identification and USB cable)");
        }
        YAPI.FreeAPI();
    }
}
 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

import com.yoctopuce.YoctoAPI.*;

public class Demo {

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }

        if (args.length != 2) {
            System.out.println("usage: demo <serial or logical name> <new logical name>");
            System.exit(1);
        }

        YModule m;
        String newname;

        m = YModule.FindModule(args[0]); // use serial or logical name

        try {
            newname = args[1];
            if (!YAPI.CheckLogicalName(newname))
                {
                    System.out.println("Invalid name (" + newname + ")");
                    System.exit(1);
                }

            m.set_logicalName(newname);
            m.saveToFlash(); // do not forget this

            System.out.println("Module: serial= " + m.get_serialNumber());
            System.out.println(" / name= " + m.get_logicalName());
        } catch (YAPI_Exception ex) {
            System.out.println("Module " + args[0] + "not connected (check identification and USB cable)");
            System.out.println(ex.getMessage());
            System.exit(1);
        }

        YAPI.FreeAPI();
    }
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

import com.yoctopuce.YoctoAPI.*;

public class Demo {

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }

        System.out.println("Device list");
        YModule module = YModule.FirstModule();
        while (module != null) {
            try {
                System.out.println(module.get_serialNumber() + " (" + module.get_productName() + ")");
            } catch (YAPI_Exception ex) {
                break;
            }
            module = module.nextModule();
        }
        YAPI.FreeAPI();
    }
}
 

17.4. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software.

In the Java API, error handling is implemented with exceptions. Therefore you must catch and handle correctly all exceptions that might be thrown by the API if you do not want your software to crash as soon as you unplug a device.

18. Using the Yocto-SPI with Android

To tell the truth, Android is not a programming language, it is an operating system developed by Google for mobile appliances such as smart phones and tablets. But it so happens that under Android everything is programmed with the same programming language: Java. Nevertheless, the programming paradigms and the possibilities to access the hardware are slightly different from classical Java, and this justifies a separate chapter on Android programming.

18.1. Native access and VirtualHub

In the opposite to the classical Java API, the Java for Android API can access USB modules natively. However, as there is no VirtualHub running under Android, it is not possible to remotely control Yoctopuce modules connected to a machine under Android. Naturally, the Java for Android API remains perfectly able to connect itself to a VirtualHub running on another OS.

18.2. Getting ready

Go to the Yoctopuce web site and download the Java for Android programming library43. The library is available as source files, and also as a jar file. Connect your modules, decompress the library files in the directory of your choice, and configure your Android programming environment so that it can find them.

To keep them simple, all the examples provided in this documentation are snippets of Android applications. You must integrate them in your own Android applications to make them work. However, your can find complete applications in the examples provided with the Java for Android library.

18.3. Compatibility

In an ideal world, you would only need to have a smart phone running under Android to be able to make Yoctopuce modules work. Unfortunately, it is not quite so in the real world. A machine running under Android must fulfil to a few requirements to be able to manage Yoctopuce USB modules natively.

Android 4.x

Android 4.0 (api 14) and following are officially supported. Theoretically, support of USB host functions since Android 3.1. But be aware that the Yoctopuce Java for Android API is regularly tested only from Android 4 onwards.

USB host support

Naturally, not only must your machine have a USB port, this port must also be able to run in host mode. In host mode, the machine literally takes control of the devices which are connected to it. The USB ports of a desktop computer, for example, work in host mode. The opposite of the host mode is the device mode. USB keys, for instance, work in device mode: they must be controlled by a host. Some USB ports are able to work in both modes, they are OTG (On The Go) ports. It so happens that many mobile devices can only work in device mode: they are designed to be connected to a charger or a desktop computer, and nothing else. It is therefore highly recommended to pay careful attention to the technical specifications of a product working under Android before hoping to make Yoctopuce modules work with it.

Unfortunately, having a correct version of Android and USB ports working in host mode is not enough to guaranty that Yoctopuce modules will work well under Android. Indeed, some manufacturers configure their Android image so that devices other than keyboard and mass storage are ignored, and this configuration is hard to detect. As things currently stand, the best way to know if a given Android machine works with Yoctopuce modules consists in trying.

Supported hardware

The library is tested and validated on the following machines:

If your Android machine is not able to control Yoctopuce modules natively, you still have the possibility to remotely control modules driven by a VirtualHub on another OS, or a YoctoHub 44.

18.4. Activating the USB port under Android

By default, Android does not allow an application to access the devices connected to the USB port. To enable your application to interact with a Yoctopuce module directly connected on your tablet on a USB port, a few additional steps are required. If you intend to interact only with modules connected on another machine through the network, you can ignore this section.

In your AndroidManifest.xml, you must declare using the "USB Host" functionality by adding the <uses-feature android:name="android.hardware.usb.host" /> tag in the manifest section.


<manifest ...>
    ...
    <uses-feature android:name="android.hardware.usb.host" />;
    ...
</manifest>

When first accessing a Yoctopuce module, Android opens a window to inform the user that the application is going to access the connected module. The user can deny or authorize access to the device. If the user authorizes the access, the application can access the connected device as long as it stays connected. To enable the Yoctopuce library to correctly manage these authorizations, your must provide a pointer on the application context by calling the EnableUSBHost method of the YAPI class before the first USB access. This function takes as arguments an object of the android.content.Context class (or of a subclass). As the Activity class is a subclass of Context, it is simpler to call YAPI.EnableUSBHost(this); in the method onCreate of your application. If the object passed as parameter is not of the correct type, a YAPI_Exception exception is generated.


...
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    try {
                // Pass the application Context to the Yoctopuce Library
        YAPI.EnableUSBHost(this);
        } catch (YAPI_Exception e) {
                Log.e("Yocto",e.getLocalizedMessage());
        }
}
...

Autorun

It is possible to register your application as a default application for a USB module. In this case, as soon as a module is connected to the system, the application is automatically launched. You must add <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"/> in the section <intent-filter> of the main activity. The section <activity> must have a pointer to an XML file containing the list of USB modules which can run the application.


<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    ...
    <uses-feature android:name="android.hardware.usb.host" />
    ...
    <application ... >
        <activity
            android:name=".MainActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
                android:resource="@xml/device_filter" />
        </activity>
    </application>

</manifest>

The XML file containing the list of modules allowed to run the application must be saved in the res/xml directory. This file contains a list of USB vendorId and deviceID in decimal. The following example runs the application as soon as a Yocto-Relay or a YoctoPowerRelay is connected. You can find the vendorID and the deviceID of Yoctopuce modules in the characteristics section of the documentation.


<?xml version="1.0" encoding="utf-8"?>

<resources>
    <usb-device vendor-id="9440" product-id="12" />
    <usb-device vendor-id="9440" product-id="13" />
</resources>

18.5. Control of the SpiPort function

A few lines of code are enough to use a Yocto-SPI. Here is the skeleton of a Java code snippet to use the SpiPort function.


[...]

// Retrieving the object representing the module (connected here locally by USB)
YAPI.EnableUSBHost(this);
YAPI.RegisterHub("usb");
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort");

// Hot-plug is easy: just check that the device is online
if (spiport.isOnline())
   { //Use spiport.set_spiMode()
     ...
   }

[...]

Let us look at these lines in more details.

YAPI.EnableUSBHost

The YAPI.EnableUSBHost function initializes the API with the Context of the current application. This function takes as argument an object of the android.content.Context class (or of a subclass). If you intend to connect your application only to other machines through the network, this function is facultative.

YAPI.RegisterHub

The yAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. The parameter is the address of the virtual hub able to see the devices. If the string "usb" is passed as parameter, the API works with modules locally connected to the machine. If the initialization does not succeed, an exception is thrown.

YSpiPort.FindSpiPort

The YSpiPort.FindSpiPort function allows you to find a SPI port from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-SPI module with serial number YSPIMK01-123456 which you have named "MyModule", and for which you have given the spiPort function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.spiPort")
spiport = YSpiPort.FindSpiPort("YSPIMK01-123456.MyFunction")
spiport = YSpiPort.FindSpiPort("MyModule.spiPort")
spiport = YSpiPort.FindSpiPort("MyModule.MyFunction")
spiport = YSpiPort.FindSpiPort("MyFunction")

YSpiPort.FindSpiPort returns an object which you can then use at will to control the SPI port.

isOnline

The isOnline() method of the object returned by YSpiPort.FindSpiPort allows you to know if the corresponding module is present and in working order.

set_spiMode, set_ssPolarity, set_protocol

These methods of the object returned by YSpiPort.FindSpiPort define the communication parameters used on the SPI port. The parameters must match those of the slave device, or communication will not work. This demo example is intended to be used with a MAX7219 7-segment display driver. Note that you must also configure the electrical levels, which is intentionally not done in this example in order to prevent an accidental damage to your slave device in case you would start this code without thinking about it.

reset

The reset() method of the object returned by YSpiPort.FindSpiPort empties all the SPI port buffers.

writeHex

The writeHex() method transmits on the SPI port the message given in hexadecimal form. It is convenient for fixed messages.

writeArray

The writeHex() method transmits on the SPI port the message given as a list of integers. It is more convenient for computed messages.

A real example

Launch you Java environment and open the corresponding sample project provided in the directory Examples//Doc-Examples of the Yoctopuce library.

In this example, you can recognize the functions explained above, but this time used with all the side materials needed to make it work nicely as a small demo.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.SeekBar;
import android.widget.Spinner;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YPwmOutput;
import com.yoctopuce.YoctoAPI.YSpiPort;

import java.util.ArrayList;

public class GettingStarted_Yocto_SPI extends Activity implements OnItemSelectedListener
{

    private YSpiPort _spiPort = null;
    private ArrayAdapter<String> aa;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.gettingstarted_yocto_spi);
        Spinner my_spin = (Spinner) findViewById(R.id.spinner1);
        my_spin.setOnItemSelectedListener(this);
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        my_spin.setAdapter(aa);
    }

    @Override
    protected void onStart()
    {
        super.onStart();
        aa.clear();
        try {
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
            YSpiPort s = YSpiPort.FirstSpiPort();
            while (s != null) {
                String hwid = s.get_hardwareId();
                aa.add(hwid);
                s = s.nextSpiPort();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        aa.notifyDataSetChanged();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
    {
        String hwid = (String) parent.getItemAtPosition(pos);
        _spiPort = YSpiPort.FindSpiPort(hwid);
        try {
            _spiPort.set_spiMode("250000,2,msb");
            _spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW);
            _spiPort.set_protocol("Frame:5ms");
            _spiPort.reset();
            _spiPort.writeHex("0c01"); // Exit from shutdown state
            _spiPort.writeHex("09ff"); // Enable BCD for all digits
            _spiPort.writeHex("0b07"); // Enable digits 0-7 (=8 in total)
            _spiPort.writeHex("0a0a"); // Set medium brightness
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0)
    {
    }

    /**
     * Called when the user touches the button State A
     */

    public void update(View view)
    {
        if (_spiPort == null)
            return;

        EditText editText = (EditText) findViewById(R.id.value);

        int value;
        try {
            value = Integer.valueOf(editText.getText().toString());
        } catch (NumberFormatException ex) {
            return;
        }
        try {
            for (int i = 1; i <= 8; i++) {
                int digit = value % 10;
                ArrayList<Integer> dataToWrite = new ArrayList<>();
                dataToWrite.add(i);
                dataToWrite.add(digit);
                _spiPort.writeArray(dataToWrite);
                value = value / 10;
            }

        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }

    }

}
 

18.6. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Switch;
import android.widget.TextView;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YModule;

public class ModuleControl extends Activity implements OnItemSelectedListener
{

    private ArrayAdapter<String> aa;
    private YModule module = null;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.modulecontrol);
        Spinner my_spin = (Spinner) findViewById(R.id.spinner1);
        my_spin.setOnItemSelectedListener(this);
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        my_spin.setAdapter(aa);
    }

    @Override
    protected void onStart()
    {
        super.onStart();

        try {
            aa.clear();
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
            YModule r = YModule.FirstModule();
            while (r != null) {
                String hwid = r.get_hardwareId();
                aa.add(hwid);
                r = r.nextModule();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        // refresh Spinner with detected relay
        aa.notifyDataSetChanged();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

    private void DisplayModuleInfo()
    {
        TextView field;
        if (module == null)
            return;
        try {
            field = (TextView) findViewById(R.id.serialfield);
            field.setText(module.getSerialNumber());
            field = (TextView) findViewById(R.id.logicalnamefield);
            field.setText(module.getLogicalName());
            field = (TextView) findViewById(R.id.luminosityfield);
            field.setText(String.format("%d%%", module.getLuminosity()));
            field = (TextView) findViewById(R.id.uptimefield);
            field.setText(module.getUpTime() / 1000 + " sec");
            field = (TextView) findViewById(R.id.usbcurrentfield);
            field.setText(module.getUsbCurrent() + " mA");
            Switch sw = (Switch) findViewById(R.id.beaconswitch);
            sw.setChecked(module.getBeacon() == YModule.BEACON_ON);
            field = (TextView) findViewById(R.id.logs);
            field.setText(module.get_lastLogs());

        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
    {
        String hwid = parent.getItemAtPosition(pos).toString();
        module = YModule.FindModule(hwid);
        DisplayModuleInfo();
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0)
    {
    }

    public void refreshInfo(View view)
    {
        DisplayModuleInfo();
    }

    public void toggleBeacon(View view)
    {
        if (module == null)
            return;
        boolean on = ((Switch) view).isChecked();

        try {
            if (on) {
                module.setBeacon(YModule.BEACON_ON);
            } else {
                module.setBeacon(YModule.BEACON_OFF);
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }
}
 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YModule;

public class SaveSettings extends Activity implements OnItemSelectedListener
{

    private ArrayAdapter<String> aa;
    private YModule module = null;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.savesettings);
        Spinner my_spin = (Spinner) findViewById(R.id.spinner1);
        my_spin.setOnItemSelectedListener(this);
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        my_spin.setAdapter(aa);
    }

    @Override
    protected void onStart()
    {
        super.onStart();

        try {
            aa.clear();
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
            YModule r = YModule.FirstModule();
            while (r != null) {
                String hwid = r.get_hardwareId();
                aa.add(hwid);
                r = r.nextModule();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        // refresh Spinner with detected relay
        aa.notifyDataSetChanged();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

    private void DisplayModuleInfo()
    {
        TextView field;
        if (module == null)
            return;
        try {
            YAPI.UpdateDeviceList();// fixme
            field = (TextView) findViewById(R.id.logicalnamefield);
            field.setText(module.getLogicalName());
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
    {
        String hwid = parent.getItemAtPosition(pos).toString();
        module = YModule.FindModule(hwid);
        DisplayModuleInfo();
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0)
    {
    }

    public void saveName(View view)
    {
        if (module == null)
            return;

        EditText edit = (EditText) findViewById(R.id.newname);
        String newname = edit.getText().toString();
        try {
            if (!YAPI.CheckLogicalName(newname)) {
                Toast.makeText(getApplicationContext(), "Invalid name (" + newname + ")", Toast.LENGTH_LONG).show();
                return;
            }
            module.set_logicalName(newname);
            module.saveToFlash(); // do not forget this
            edit.setText("");
        } catch (YAPI_Exception ex) {
            ex.printStackTrace();
        }
        DisplayModuleInfo();
    }

}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YModule;

public class Inventory extends Activity
{

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.inventory);
    }

    public void refreshInventory(View view)
    {
        LinearLayout layout = (LinearLayout) findViewById(R.id.inventoryList);
        layout.removeAllViews();

        try {
            YAPI.UpdateDeviceList();
            YModule module = YModule.FirstModule();
            while (module != null) {
                String line = module.get_serialNumber() + " (" + module.get_productName() + ")";
                TextView tx = new TextView(this);
                tx.setText(line);
                tx.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);
                layout.addView(tx);
                module = module.nextModule();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onStart()
    {
        super.onStart();
        try {
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        refreshInventory(null);
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

}
 

18.7. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software.

In the Java API for Android, error handling is implemented with exceptions. Therefore you must catch and handle correctly all exceptions that might be thrown by the API if you do not want your software to crash soon as you unplug a device.

19. Advanced programming

The preceding chapters have introduced, in each available language, the basic programming functions which can be used with your Yocto-SPI module. This chapter presents in a more generic manner a more advanced use of your module. Examples are provided in the language which is the most popular among Yoctopuce customers, that is C#. Nevertheless, you can find complete examples illustrating the concepts presented here in the programming libraries of each language.

To remain as concise as possible, examples provided in this chapter do not perform any error handling. Do not copy them "as is" in a production application.

19.1. Event programming

The methods to manage Yoctopuce modules which we presented to you in preceding chapters were polling functions, consisting in permanently asking the API if something had changed. While easy to understand, this programming technique is not the most efficient, nor the most reactive. Therefore, the Yoctopuce programming API also provides an event programming model. This technique consists in asking the API to signal by itself the important changes as soon as they are detected. Each time a key parameter is modified, the API calls a callback function which you have defined in advance.

Detecting module arrival and departure

Hot-plug management is important when you work with USB modules because, sooner or later, you will have to connect or disconnect a module when your application is running. The API is designed to manage module unexpected arrival or departure in a transparent way. But your application must take this into account if it wants to avoid pretending to use a disconnected module.

Event programming is particularly useful to detect module connection/disconnection. Indeed, it is simpler to be told of new connections rather than to have to permanently list the connected modules to deduce which ones just arrived and which ones left. To be warned as soon as a module is connected, you need three pieces of code.

The callback

The callback is the function which is called each time a new Yoctopuce module is connected. It takes as parameter the relevant module.


 static void deviceArrival(YModule m)
{
  Console.WriteLine("New module  : " + m.get_serialNumber());
}

Initialization

You must then tell the API that it must call the callback when a new module is connected.


YAPI.RegisterDeviceArrivalCallback(deviceArrival);

Note that if modules are already connected when the callback is registered, the callback is called for each of the already connected modules.

Triggering callbacks

A classis issue of callback programming is that these callbacks can be triggered at any time, including at times when the main program is not ready to receive them. This can have undesired side effects, such as dead-locks and other race conditions. Therefore, in the Yoctopuce API, module arrival/departure callbacks are called only when the UpdateDeviceList() function is running. You only need to call UpdateDeviceList() at regular intervals from a timer or from a specific thread to precisely control when the calls to these callbacks happen:


// waiting loop managing callbacks
while (true)
{
    // module arrival / departure callback
    YAPI.UpdateDeviceList(ref errmsg);
    // non active waiting time managing other callbacks
    YAPI.Sleep(500, ref errmsg);
}

In a similar way, it is possible to have a callback when a module is disconnected. You can find a complete example implemented in your favorite programming language in the Examples/Prog-EventBased directory of the corresponding library.

Be aware that in most programming languages, callbacks must be global procedures, and not methods. If you wish for the callback to call the method of an object, define your callback as a global procedure which then calls your method.

Detecting a modification in the value of a sensor

The Yoctopuce API also provides a callback system allowing you to be notified automatically with the value of any sensor, either when the value has changed in a significant way or periodically at a preset frequency. The code necessary to do so is rather similar to the code used to detect when a new module has been connected.

This technique is useful in particular if you want to detect very quick value changes (within a few milliseconds), as it is much more efficient than reading repeatedly the sensor value and therefore gives better performances.

Calliback invocation

To enable a better control, value change callbacks are only called when the YAPI.Sleep() and YAPI.HandleEvents() functions are running. Therefore, you must call one of these functions at a regular interval, either from a timer or from a parallel thread.


while (true)
{
  // inactive waiting loop allowing you to trigger
  // value change callbacks
  YAPI.Sleep(500, ref errmsg);
}

In programming environments where only the interface thread is allowed to interact with the user, it is often appropriate to call YAPI.HandleEvents() from this thread.

The value change callback

This type of callback is called when a generic sensor changes in a significant way. It takes as parameter the relevant function and the new value, as a character string. 45


static void valueChangeCallback(YGenericSensor fct, string value)
{
  Console.WriteLine(fct.get_hardwareId() + "=" + value);
}

In most programming languages, callbacks are global procedures, not methods. If you wish for the callback to call a method of an object, define your callback as a global procedure which then calls your method. If you need to keep a reference to your object, you can store it directly in the YGenericSensor object using function set_userData. You can then retrieve it in the global callback procedure using get_userData.

Setting up a value change callback

The callback is set up for a given GenericSensor function with the help of the registerValueCallback method. The following example sets up a callback for the first available GenericSensor function.


YGenericSensor f = YGenericSensor.FirstGenericSensor();
f.registerValueCallback(genericSensor1ChangeCallBack)

Note that each module function can thus have its own distinct callback. By the way, if you like to work with value change callbacks, you will appreciate the fact that value change callbacks are not limited to sensors, but are also available for all Yoctopuce devices (for instance, you can also receive a callback any time a relay state changes).

The timed report callback

This type of callback is automatically called at a predefined time interval. The callback frequency can be configured individually for each sensor, with frequencies going from hundred calls per seconds down to one call per hour. The callback takes as parameter the relevant function and the measured value, as an YMeasure object. Contrarily to the value change callback that only receives the latest value, an YMeasure object provides both minimal, maximal and average values since the timed report callback. Moreover, the measure includes precise timestamps, which makes it possible to use timed reports for a time-based graph even when not handled immediately.


static void periodicCallback(YGenericSensor fct, YMeasure measure)
{
  Console.WriteLine(fct.get_hardwareId() + "=" +
                    measure.get_averageValue());
}

Setting up a timed report callback

The callback is set up for a given GenericSensor function with the help of the registerTimedReportCallback method. The callback will only be invoked once a callback frequency as been set using set_reportFrequency (which defaults to timed report callback turned off). The frequency is specified as a string (same as for the data logger), by specifying the number of calls per second (/s), per minute (/m) or per hour (/h). The maximal frequency is 100 times per second (i.e. "100/s"), and the minimal frequency is 1 time per hour (i.e. "1/h"). When the frequency is higher than or equal to 1/s, the measure represents an instant value. When the frequency is below, the measure will include distinct minimal, maximal and average values based on a sampling performed automatically by the device.

The following example sets up a timed report callback 4 times per minute for t he first available GenericSensor function.


YGenericSensor f = YGenericSensor.FirstGenericSensor();
f.set_reportFrequency("4/m");
f.registerTimedReportCallback(periodicCallback);

As for value change callbacks, each module function can thus have its own distinct timed report callback.

Generic callback functions

It is sometimes desirable to use the same callback function for various types of sensors (e.g. for a generic sensor graphing application). This is possible by defining the callback for an object of class YSensor rather than YGenericSensor. Thus, the same callback function will be usable with any subclass of YSensor (and in particular with YGenericSensor). With the callback function, you can use the method get_unt() to get the physical unit of the sensor, if you need to display it.

A complete example

You can find a complete example implemented in your favorite programming language in the Examples/Prog-EventBased directory of the corresponding library.

19.2. The data logger

Your Yocto-SPI is equipped with a data logger able to store non-stop the measures performed by the module. The maximal frequency is 100 times per second (i.e. "100/s"), and the minimal frequency is 1 time per hour (i.e. "1/h"). When the frequency is higher than or equal to 1/s, the measure represents an instant value. When the frequency is below, the measure will include distinct minimal, maximal and average values based on a sampling performed automatically by the device.

The data logger flash memory can store about 500'000 instant measures, or 125'000 averaged measures. When the memory is about to be saturated, the oldest measures are automatically erased.

Make sure not to leave the data logger running at high speed unless really needed: the flash memory can only stand a limited number of erase cycles (typically 100'000 cycles). When running at full speed, the datalogger can burn more than 100 cycles per day ! Also be aware that it is useless to record measures at a frequency higher than the refresh frequency of the physical sensor itself.

Starting/stopping the datalogger

The data logger can be started with the set_recording() method.


YDataLogger l = YDataLogger.FirstDataLogger();
l.set_recording(YDataLogger.RECORDING_ON);

It is possible to make the data recording start automatically as soon as the module is powered on.


YDataLogger l = YDataLogger.FirstDataLogger();
l.set_autoStart(YDataLogger.AUTOSTART_ON);
l.get_module().saveToFlash();  // do not forget to save the setting

Note: Yoctopuce modules do not need an active USB connection to work: they start working as soon as they are powered on. The Yocto-SPI can store data without necessarily being connected to a computer: you only need to activate the automatic start of the data logger and to power on the module with a simple USB charger.

Erasing the memory

The memory of the data logger can be erased with the forgetAllDataStreams() function. Be aware that erasing cannot be undone.


YDataLogger l = YDataLogger.FirstDataLogger();
l.forgetAllDataStreams();

Choosing the logging frequency

The logging frequency can be set up individually for each sensor, using the method set_logFrequency(). The frequency is specified as a string (same as for timed report callbacks), by specifying the number of calls per second (/s), per minute (/m) or per hour (/h). The default value is "1/s".

The following example configures the logging frequency at 15 measures per minute for the first sensor found, whatever its type:


YSensor sensor = YSensor.FirstSensor();
sensor.set_logFrequency("15/m");

To avoid wasting flash memory, it is possible to disable logging for specified functions. In order to do so, simply use the value "OFF":


sensor.set_logFrequency("OFF");

Limitation: The Yocto-SPI cannot use a different frequency for timed-report callbacks and for recording data into the datalogger. You can disable either of them individually, but if you enable both timed-report callbacks and logging for a given function, the two will work at the same frequency.

Retrieving the data

To load recorded measures from the Yocto-SPI flash memory, you must call the get_recordedData() method of the desired sensor, and specify the time interval for which you want to retrieve measures. The time interval is given by the start and stop UNIX timestamp. You can also specify 0 if you don't want any start or stop limit.

The get_recordedData() method does not return directly am array of measured values, since in some cases it would cause a huge load that could affect the responsiveness of the application. Instead, this function will return an YDataSet object that can be used to retrieve immediately an overview of the measured data (summary), and then to load progressively the details when desired.

Here are the main methods used to retrieve recorded measures:

  1. dataset = sensor.get_recordedData(0,0): select the desired time interval
  2. dataset.loadMore(): load data from the device, progressively
  3. dataset.get_summary(): get a single measure summarizing the full time interval
  4. dataset.get_preview(): get an array of measures representing a condensed version of the whole set of measures on the selected time interval (reduced by a factor of approx. 200)
  5. dataset.get_measures(): get an array with all detailled measures (that grows while loadMore is being called repeteadly)

Measures are instances of YMeasure 46. They store simultaneously the minimal, average and maximal value at a given time, that you can retrieve using methods get_minValue(), get_averageValue() and get_maxValue() respectively. Here is a small example that uses the functions above:


// We will retrieve all measures, without time limit
YDataSet dataset = sensor.get_recordedData(0, 0);

// First call to loadMore() loads the summary/preview
dataset.loadMore();
YMeasure summary = dataset.get_summary();
string timeFmt = "dd MMM yyyy hh:mm:ss,fff";
string logFmt = "from {0} to {1} : average={2:0.00}{3}";
Console.WriteLine(String.Format(logFmt,
    summary.get_startTimeUTC_asDateTime().ToString(timeFmt),
    summary.get_endTimeUTC_asDateTime().ToString(timeFmt),
    summary.get_averageValue(), sensor.get_unit()));

// Next calls to loadMore() will retrieve measures
Console.WriteLine("loading details");
int progress;
do {
    Console.Write(".");
    progress = dataset.loadMore();
} while(progress < 100);

// All measures have now been loaded
List<YMeasure> details = dataset.get_measures();
foreach (YMeasure m in details) {
    Console.WriteLine(String.Format(logFmt,
        m.get_startTimeUTC_asDateTime().ToString(timeFmt),
        m.get_endTimeUTC_asDateTime().ToString(timeFmt),
        m.get_averageValue(), sensor.get_unit()));
}

You will find a complete example demonstrating how to retrieve data from the logger for each programming language directly in the Yoctopuce library. The example can be found in directory Examples/Prog-DataLogger.

Timestamp

As the Yocto-SPI does not have a battery, it cannot guess alone the current time when powered on. Nevertheless, the Yocto-SPI will automatically try to adjust its real-time reference using the host to which it is connected, in order to properly attach a timestamp to each measure in the datalogger:

When none of these conditions applies (for instance if the module is simply connected to an USB charger), the Yocto-SPI will do its best effort to attach a reasonable timestamp to the measures, using the timestamp found on the latest recorded measures. It is therefore possible to "preset to the real time" an autonomous Yocto-SPI by connecting it to an Android mobile phone, starting the data logger, then connecting the device alone on an USB charger. Nevertheless, be aware that without external time source, the internal clock of the Yocto-SPI might be be subject to a clock skew (theoretically up to 0.3%).

19.3. Sensor calibration

Your Yocto-SPI module is equipped with a digital sensor calibrated at the factory. The values it returns are supposed to be reasonably correct in most cases. There are, however, situations where external conditions can impact the measures.

The Yoctopuce API provides the mean to re-caliber the values measured by your Yocto-SPI. You are not going to modify the hardware settings of the module, but rather to transform afterwards the measures taken by the sensor. This transformation is controlled by parameters stored in the flash memory of the module, making it specific for each module. This re-calibration is therefore a fully software matter and remains perfectly reversible.

Before deciding to re-calibrate your Yocto-SPI module, make sure you have well understood the phenomena which impact the measures of your module, and that the differences between true values and measured values do not result from a incorrect use or an inadequate location of the module.

The Yoctopuce modules support two types of calibration. On the one hand, a linear interpolation based on 1 to 5 reference points, which can be performed directly inside the Yocto-SPI. On the other hand, the API supports an external arbitrary calibration, implemented with callbacks.

1 to 5 point linear interpolation

These transformations are performed directly inside the Yocto-SPI which means that you only have to store the calibration points in the module flash memory, and all the correction computations are done in a perfectly transparent manner: The function get_currentValue() returns the corrected value while the function get_currentRawValue() keeps returning the value before the correction.

Calibration points are simply (Raw_value, Corrected_value) couples. Let us look at the impact of the number of calibration points on the corrections.

1 point correction

The 1 point correction only adds a shift to the measures. For example, if you provide the calibration point (a, b), all the measured values are corrected by adding to them b-a, so that when the value read on the sensor is a, the genericSensor1 function returns b.


Measure correction with 1 calibration point, here (5,10)

The application is very simple: you only need to call the calibrateFromPoints() method of the function you wish to correct. The following code applies the correction illustrated on the graph above to the first genericSensor1 function found. Note the call to the saveToFlash method of the module hosting the function, so that the module does not forget the calibration as soon as it is disconnected.


Double[] ValuesBefore = {5};
Double[] ValuesAfter  = {10};
YGenericSensor f = YGenericSensor.FirstGenericSensor();
f.calibrateFromPoints(ValuesBefore, ValuesAfter);
f.get_module().saveToFlash();

2 point correction

2 point correction allows you to perform both a shift and a multiplication by a given factor between two points. If you provide the two points (a, b) and (c, d), the function result is multiplied (d-b)/(c-a) in the [a, c] range and shifted, so that when the value read by the sensor is a or c, the genericSensor1 function returns respectively b and d. Outside of the [a, c] range, the values are simply shifted, so as to preserve the continuity of the measures: an increase of 1 on the value read by the sensor induces an increase of 1 on the returned value.


Measure correction with the two calibration points (10,5) and (25,10).

The code allowing you to program this calibration is very similar to the preceding code example.


Double[] ValuesBefore = {10,25};
Double[] ValuesAfter  = {5,10};
YGenericSensor f = YGenericSensor.FirstGenericSensor();
f.calibrateFromPoints(ValuesBefore, ValuesAfter);
f.get_module().saveToFlash();

Note that the values before correction must be sorted in a strictly ascending order, otherwise they are simply ignored.

3 to 5 point correction

3 to 5 point corrections are only a generalization of the 2 point method, allowing you to create up to 4 correction ranges for an increased precision. These ranges cannot be disjoint.


Correction example with 3 calibration points

Back to normal

To cancel the effect of a calibration on a function, call the calibrateFromPoints() method with two empty arrays.


Double[] ValuesBefore = {};
Double[] ValuesAfter  = {};
YGenericSensor f = YGenericSensor.FirstGenericSensor();
f.calibrateFromPoints(ValuesBefore, ValuesAfter);
f.get_module().saveToFlash();

You will find, in the Examples\Prog-Calibration directory of the Delphi, VB, and C# libraries, an application allowing you to test the effects of the 1 to 5 point calibration.

Arbitrary interpolation

It is also possible to compute the interpolation instead of letting the module do it, in order to calculate a spline interpolation, for instance. To do so, you only need to store a callback in the API. This callback must specify the number of calibration points it is expecting.


public static double CustomInterpolation3Points(double rawValue, int calibType,
                  int[] parameters, double[] beforeValues, double[] afterValues)
  {  double result;
     // the value to be corrected is rawValue
     // calibration points are in beforeValues and afterValues
     result = ....    // interpolation of your choice
     return result;
   }
YAPI.RegisterCalibrationHandler(3, CustomInterpolation3Points);

Note that these interpolation callbacks are global, and not specific to each function. Thus, each time someone requests a value from a module which contains in its flash memory the correct number of calibration points, the corresponding callback is called to correct the value before returning it, enabling thus a perfectly transparent measure correction.

20. Firmware Update

There are multiples way to update the firmware of a Yoctopuce module..

20.1. The VirtualHub or the YoctoHub

It is possible to update the firmware directly from the web interface of the VirtualHub or the YoctoHub. The configuration panel of the module has an "upgrade" button to start a wizard that will guide you through the firmware update procedure.

In case the firmware update fails for any reason, and the module does no start anymore, simply unplug the module then plug it back while maintaining the Yocto-button down. The module will boot in "firmware update" mode and will appear in the VirtualHub interface below the module list.

20.2. The command line library

All the command line tools can update Yoctopuce modules thanks to the downloadAndUpdate command. The module selection mechanism works like for a traditional command. The [target] is the name of the module that you want to update. You can also use the "any" or "all" aliases, or even a name list, where the names are separated by commas, without spaces.


C:\>Executable [options] [target] command [parameters]

The following example updates all the Yoctopuce modules connected by USB.


C:\>YModule all downloadAndUpdate
ok: Yocto-PowerRelay RELAYHI1-266C8(rev=15430) is up to date.
ok: 0 / 0 hubs in 0.000000s.
ok: 0 / 0 shields in 0.000000s.
ok: 1 / 1 devices in 0.130000s 0.130000s per device.
ok: All devices are now up to date.
C:\>

20.3. The Android application Yocto-Firmware

You can update your module firmware from your Android phone or tablet with the Yocto-Firmware application. This application lists all the Yoctopuce modules connected by USB and checks if a more recent firmware is available on www.yoctopuce.com. If a more recent firmware is available, you can update the module. The application is responsible for downloading and installing the new firmware while preserving the module parameters.

Please note: while the firmware is being updated, the module restarts several times. Android interprets a USB device reboot as a disconnection and reconnection of the USB device and asks the authorization to use the USB port again. The user must click on OK for the update process to end successfully.

20.4. Updating the firmware with the programming library

If you need to integrate firmware updates in your application, the libraries offer you an API to update your modules. 47

Saving and restoring parameters

The get_allSettings() method returns a binary buffer enabling you to save a module persistent parameters. This function is very useful to save the network configuration of a YoctoHub for example.


YWireless wireless = YWireless.FindWireless("reference");
YModule m = wireless.get_module();
byte[] default_config =  m.get_allSettings();
saveFile("default.bin", default_config);
...

You can then apply these parameters to other modules with the set_allSettings() method.


byte[] default_config = loadFile("default.bin");
YModule m = YModule.FirstModule();
while (m != null) {
  if (m.get_productName() == "YoctoHub-Wireless") {
    m.set_allSettings(default_config);
  }
  m = m.next();
}

Finding the correct firmware

The first step to update a Yoctopuce module is to find which firmware you must use. The checkFirmware(path, onlynew) method of the YModule object does exactly this. The method checks that the firmware given as argument (path) is compatible with the module. If the onlynew parameter is set, this method checks that the firmware is more recent than the version currently used by the module. When the file is not compatible (or if the file is older than the installed version), this method returns an empty string. In the opposite, if the file is valid, the method returns a file access path.

The following piece of code checks that the c:\tmp\METEOMK1.17328.byn is compatible with the module stored in the m variable .


YModule m = YModule.FirstModule();
...
...
string path = "c:\\tmp\METEOMK1.17328.byn";
string newfirm = m.checkFirmware(path, false);
if (newfirm != "") {
  Console.WriteLine("firmware " + newfirm + " is compatible");
}
...

The argument can be a directory (instead of a file). In this case, the method checks all the files of the directory recursively and returns the most recent compatible firmware. The following piece of code checks whether there is a more recent firmware in the c:\tmp\ directory.


YModule m = YModule.FirstModule();
...
...
string path = "c:\\tmp";
string newfirm = m.checkFirmware(path, true);
if (newfirm != "") {
  Console.WriteLine("firmware " + newfirm + " is compatible and newer");
}
...

You can also give the "www.yoctopuce.com" string as argument to check whether there is a more recent published firmware on Yoctopuce's web site. In this case, the method returns the firmware URL. You can use this URL to download the firmware on your disk or use this URL when updating the firmware (see below). Obviously, this possibility works only if your machine is connected to Internet.


YModule m = YModule.FirstModule();
...
...
string url = m.checkFirmware("www.yoctopuce.com", true);
if (url != "") {
  Console.WriteLine("new firmware is available at " + url );
}
...

Updating the firmware

A firmware update can take several minutes. That is why the update process is run as a background task and is driven by the user code thanks to the YFirmwareUdpate class.

To update a Yoctopuce module, you must obtain an instance of the YFirmwareUdpate class with the updateFirmware method of a YModule object. The only parameter of this method is the path of the firmware that you want to install. This method does not immediately start the update, but returns a YFirmwareUdpate object configured to update the module.


string newfirm = m.checkFirmware("www.yoctopuce.com", true);
.....
YFirmwareUpdate fw_update = m.updateFirmware(newfirm);

The startUpdate() method starts the update as a background task. This background task automatically takes care of

  1. saving the module parameters
  2. restarting the module in "update" mode
  3. updating the firmware
  4. starting the module with the new firmware version
  5. restoring the parameters

The get_progress() and get_progressMessage() methods enable you to follow the progression of the update. get_progress() returns the progression as a percentage (100 = update complete). get_progressMessage() returns a character string describing the current operation (deleting, writing, rebooting, ...). If the get_progress method returns a negative value, the update process failed. In this case, the get_progressMessage() returns an error message.

The following piece of code starts the update and displays the progress on the standard output.


YFirmwareUpdate fw_update = m.updateFirmware(newfirm);
....
int status = fw_update.startUpdate();
while (status < 100 && status >= 0) {
  int newstatus = fw_update.get_progress();
  if (newstatus != status) {
    Console.WriteLine(status + "% "
      + fw_update.get_progressMessage());
  }
  YAPI.Sleep(500, ref errmsg);
  status = newstatus;
}

if (status < 0) {
  Console.WriteLine("Firmware Update failed: "
    + fw_update.get_progressMessage());
} else {
  Console.WriteLine("Firmware Updated Successfully!");
}

An Android characteristic

You can update a module firmware using the Android library. However, for modules connected by USB, Android asks the user to authorize the application to access the USB port.

During firmware update, the module restarts several times. Android interprets a USB device reboot as a disconnection and a reconnection to the USB port, and prevents all USB access as long as the user has not closed the pop-up window. The use has to click on OK for the update process to continue correctly. You cannot update a module connected by USB to an Android device without having the user interacting with the device.

20.5. The "update" mode

If you want to erase all the parameters of a module or if your module does not start correctly anymore, you can install a firmware from the "update" mode.

To force the module to work in "update" mode, disconnect it, wait a few seconds, and reconnect it while maintaining the Yocto-button down. This will restart the module in "update" mode. This update mode is protected against corruptions and is always available.

In this mode, the module is not detected by the YModule objects anymore. To obtain the list of connected modules in "update" mode, you must use the YAPI.GetAllBootLoaders() function. This function returns a character string array with the serial numbers of the modules in "update" mode.


List<string> allBootLoader = YAPI.GetAllBootLoaders();

The update process is identical to the standard case (see the preceding section), but you must manually instantiate the YFirmwareUpdate object instead of calling module.updateFirmware(). The constructor takes as argument three parameters: the module serial number, the path of the firmware to be installed, and a byte array with the parameters to be restored at the end of the update (or null to restore default parameters).


YFirmwareUpdateupdate fw_update;
fw_update = new YFirmwareUpdate(allBootLoader[0], newfirm, null);
int status = fw_update.startUpdate();
.....

21. Using with unsupported languages

Yoctopuce modules can be driven from most common programming languages. New languages are regularly added, depending on the interest expressed by Yoctopuce product users. Nevertheless, some languages are not, and will never be, supported by Yoctopuce. There can be several reasons for this: compilers which are not available anymore, unadapted environments, etc.

However, there are alternative methods to access Yoctopuce modules from an unsupported programming language.

21.1. Command line

The easiest method to drive Yoctopuce modules from an unsupported programming language is to use the command line API through system calls. The command line API is in fact made of a group of small executables which are easy to call. Their output is also easy to analyze. As most programming languages allow you to make system calls, the issue is solved with a few lines of code.

However, if the command line API is the easiest solution, it is neither the fastest nor the most efficient. For each call, the executable must initialize its own API and make an inventory of USB connected modules. This requires about one second per call.

21.2. VirtualHub and HTTP GET

The VirtualHub is available on almost all current platforms. It is generally used as a gateway to provide access to Yoctopuce modules from languages which prevent direct access to hardware layers of a computer (JavaScript, PHP, Java, ...).

In fact, the VirtualHub is a small web server able to route HTTP requests to Yoctopuce modules. This means that if you can make an HTTP request from your programming language, you can drive Yoctopuce modules, even if this language is not officially supported.

REST interface

At a low level, the modules are driven through a REST API. Thus, to control a module, you only need to perform appropriate requests on the VirtualHub. By default, the VirtualHub HTTP port is 4444.

An important advantage of this technique is that preliminary tests are very easy to implement. You only need a VirtualHub and a simple web browser. If you copy the following URL in your preferred browser, while the VirtualHub is running, you obtain the list of the connected modules.


http://127.0.0.1:4444/api/services/whitePages.txt

Note that the result is displayed as text, but if you request whitePages.xml, you obtain an XML result. Likewise, whitePages.json allows you to obtain a JSON result. The html extension even allows you to display a rough interface where you can modify values in real time. The whole REST API is available in these different formats.

Driving a module through the REST interface

Each Yoctopuce module has its own REST interface, available in several variants. Let us imagine a Yocto-SPI with the YSPIMK01-12345 serial number and the myModule logical name. The following URL allows you to know the state of the module.


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/api/module.txt

You can naturally also use the module logical name rather than its serial number.


http://127.0.0.1:4444/byName/myModule/api/module.txt

To retrieve the value of a module property, simply add the name of the property below module. For example, if you want to know the signposting led luminosity, send the following request:


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/api/module/luminosity

To change the value of a property, modify the corresponding attribute. Thus, to modify the luminosity, send the following request:


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/api/module?luminosity=100

Driving the module functions through the REST interface

The module functions can be manipulated in the same way. To know the state of the genericSensor1 function, build the following URL:


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/api/genericSensor1.txt

Note that if you can use logical names for the modules instead of their serial number, you cannot use logical names for functions. Only hardware names are authorized to access functions.

You can retrieve a module function attribute in a way rather similar to that used with the modules. For example:


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/api/genericSensor1/logicalName

Rather logically, attributes can be modified in the same manner.


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/api/genericSensor1?logicalName=myFunction

You can find the list of available attributes for your Yocto-SPI at the beginning of the Programming chapter.

Accessing Yoctopuce data logger through the REST interface

This section only applies to devices with a built-in data logger.

The preview of all recorded data streams can be retrieved in JSON format using the following URL:


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/dataLogger.json

Individual measures for any given stream can be obtained by appending the desired function identifier as well as start time of the stream:


http://127.0.0.1:4444/bySerial/YSPIMK01-12345/dataLogger.json?id=genericSensor1&utc=1389801080

21.3. Using dynamic libraries

The low level Yoctopuce API is available under several formats of dynamic libraries written in C. The sources are available with the C++ API. If you use one of these low level libraries, you do not need the VirtualHub anymore.

FilenamePlatform
libyapi.dylibMax OS X
libyapi-amd64.soLinux Intel (64 bits)
libyapi-armel.soLinux ARM EL
libyapi-armhf.soLinux ARM HL
libyapi-i386.soLinux Intel (32 bits)
yapi64.dllWindows (64 bits)
yapi.dllWindows (32 bits)

These dynamic libraries contain all the functions necessary to completely rebuild the whole high level API in any language able to integrate these libraries. This chapter nevertheless restrains itself to describing basic use of the modules.

Driving a module

The three essential functions of the low level API are the following:


int yapiInitAPI(int connection_type, char *errmsg);
int yapiUpdateDeviceList(int forceupdate, char *errmsg);
int yapiHTTPRequest(char *device, char *request, char* buffer,int buffsize,int *fullsize, char *errmsg);

The yapiInitAPI function initializes the API and must be called once at the beginning of the program. For a USB type connection, the connection_type parameter takes value 1. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

The yapiUpdateDeviceList manages the inventory of connected Yoctopuce modules. It must be called at least once. To manage hot plug and detect potential newly connected modules, this function must be called at regular intervals. The forceupdate parameter must take value 1 to force a hardware scan. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

Finally, the yapiHTTPRequest function sends HTTP requests to the module REST API. The device parameter contains the serial number or the logical name of the module which you want to reach. The request parameter contains the full HTTP request (including terminal line breaks). buffer points to a character buffer long enough to contain the answer. buffsize is the size of the buffer. fullsize is a pointer to an integer to which will be assigned the actual size of the answer. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

The format of the requests is the same as the one described in the VirtualHub et HTTP GET section. All the character strings used by the API are strings made of 8-bit characters: Unicode and UTF8 are not supported.

The resutlt returned in the buffer variable respects the HTTP protocol. It therefore includes an HTTP header. This header ends with two empty lines, that is a sequence of four ASCII characters 13, 10, 13, 10.

Here is a sample program written in pascal using the yapi.dll DLL to read and then update the luminosity of a module.


// Dll functions import
function  yapiInitAPI(mode:integer;
                      errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiInitAPI';
function  yapiUpdateDeviceList(force:integer;errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiUpdateDeviceList';
function  yapiHTTPRequest(device:pansichar;url:pansichar; buffer:pansichar;
                      buffsize:integer;var fullsize:integer;
                      errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiHTTPRequest';

var
 errmsgBuffer  : array [0..256] of ansichar;
 dataBuffer    : array [0..1024] of ansichar;
 errmsg,data   : pansichar;
 fullsize,p    : integer;

const
  serial      = 'YSPIMK01-12345';
  getValue = 'GET /api/module/luminosity HTTP/1.1'#13#10#13#10;
  setValue = 'GET /api/module?luminosity=100 HTTP/1.1'#13#10#13#10;

begin
  errmsg  :=  @errmsgBuffer;
  data    :=  @dataBuffer;
  // API  initialization
  if(yapiInitAPI(1,errmsg)<0) then
   begin
    writeln(errmsg);
    halt;
  end;

  // forces a device inventory
  if( yapiUpdateDeviceList(1,errmsg)<0) then
    begin
     writeln(errmsg);
     halt;
   end;

  // requests the  module luminosity
  if (yapiHTTPRequest(serial,getValue,data,sizeof(dataBuffer),fullsize,errmsg)<0) then
   begin
     writeln(errmsg);
     halt;
   end;

  // searches for the HTTP header end
  p := pos(#13#10#13#10,data);

  // displays the response minus the HTTP header
  writeln(copy(data,p+4,length(data)-p-3));

  // changes the luminosity
  if (yapiHTTPRequest(serial,setValue,data,sizeof(dataBuffer),fullsize,errmsg)<0) then
   begin
     writeln(errmsg);
     halt;
   end;

end.

Module inventory

To perform an inventory of Yoctopuce modules, you need two functions from the dynamic library:


 int yapiGetAllDevices(int *buffer,int maxsize,int *neededsize,char *errmsg);
 int yapiGetDeviceInfo(int devdesc,yDeviceSt *infos, char *errmsg);

The yapiGetAllDevices function retrieves the list of all connected modules as a list of handles. buffer points to a 32-bit integer array which contains the returned handles. maxsize is the size in bytes of the buffer. To neededsize is assigned the necessary size to store all the handles. From this, you can deduce either the number of connected modules or that the input buffer is too small. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

The yapiGetDeviceInfo function retrieves the information related to a module from its handle. devdesc is a 32-bit integer representing the module and which was obtained through yapiGetAllDevices. infos points to a data structure in which the result is stored. This data structure has the following format:

Name TypeSize (bytes)Description
vendorid int4Yoctopuce USB ID
deviceid int4Module USB ID
devrelease int4Module version
nbinbterfaces int4Number of USB interfaces used by the module
manufacturer char[]20Yoctopuce (null terminated)
productname char[]28Model (null terminated)
serial char[]20Serial number (null terminated)
logicalname char[]20Logical name (null terminated)
firmware char[]22Firmware version (null terminated)
beacon byte1Beacon state (0/1)

The errmsg parameter must point to a 255 character buffer to retrieve a potential error message.

Here is a sample program written in pascal using the yapi.dll DLL to list the connected modules.


// device description structure
type yDeviceSt = packed record
   vendorid        : word;
   deviceid        : word;
   devrelease      : word;
   nbinbterfaces   : word;
   manufacturer    : array [0..19] of ansichar;
   productname     : array [0..27] of ansichar;
   serial          : array [0..19] of ansichar;
   logicalname     : array [0..19] of ansichar;
   firmware        : array [0..21] of ansichar;
   beacon          : byte;
 end;

// Dll function import
function  yapiInitAPI(mode:integer;
                      errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiInitAPI';

function  yapiUpdateDeviceList(force:integer;errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiUpdateDeviceList';

function  yapiGetAllDevices( buffer:pointer;
                             maxsize:integer;
                             var neededsize:integer;
                             errmsg : pansichar):integer; cdecl;
                             external 'yapi.dll' name 'yapiGetAllDevices';

function  apiGetDeviceInfo(d:integer; var infos:yDeviceSt;
                             errmsg : pansichar):integer;  cdecl;
                             external 'yapi.dll' name 'yapiGetDeviceInfo';


var
 errmsgBuffer  : array [0..256] of ansichar;
 dataBuffer    : array [0..127] of integer;   // max of 128 USB devices
 errmsg,data   : pansichar;
 neededsize,i  : integer;
 devinfos      : yDeviceSt;

begin
  errmsg  :=  @errmsgBuffer;

  // API  initialization
  if(yapiInitAPI(1,errmsg)<0) then
   begin
    writeln(errmsg);
    halt;
  end;

   // forces a device inventory
  if( yapiUpdateDeviceList(1,errmsg)<0) then
    begin
     writeln(errmsg);
     halt;
   end;

  // loads all device handles into dataBuffer
  if yapiGetAllDevices(@dataBuffer,sizeof(dataBuffer),neededsize,errmsg)<0 then
    begin
     writeln(errmsg);
     halt;
    end;

  // gets device info from each handle
  for i:=0 to  neededsize div sizeof(integer)-1 do
   begin
     if (apiGetDeviceInfo(dataBuffer[i], devinfos, errmsg)<0) then
       begin
         writeln(errmsg);
         halt;
       end;
     writeln(pansichar(@devinfos.serial)+' ('+pansichar(@devinfos.productname)+')');
   end;

end.

VB6 and yapi.dll

Each entry point from the yapi.dll is duplicated. You will find one regular C-decl version and one Visual Basic 6 compatible version, prefixed with vb6_.

21.4. Porting the high level library

As all the sources of the Yoctopuce API are fully provided, you can very well port the whole API in the language of your choice. Note, however, that a large portion of the API source code is automatically generated.

Therefore, it is not necessary for you to port the complete API. You only need to port the yocto_api file and one file corresponding to a function, for example yocto_relay. After a little additional work, Yoctopuce is then able to generate all other files. Therefore, we highly recommend that you contact Yoctopuce support before undertaking to port the Yoctopuce library in another language. Collaborative work is advantageous to both parties.

22. High-level API Reference

This chapter summarizes the high-level API functions to drive your Yocto-SPI. Syntax and exact type names may vary from one language to another, but, unless otherwise stated, all the functions are available in every language. For detailed information regarding the types of arguments and return values for a given language, refer to the definition file for this language (yocto_api.* as well as the other yocto_* files that define the function interfaces).

For languages which support exceptions, all of these functions throw exceptions in case of error by default, rather than returning the documented error value for each function. This is by design, to facilitate debugging. It is however possible to disable the use of exceptions using the yDisableExceptions() function, in case you prefer to work with functions that return error values.

This chapter does not repeat the programming concepts described earlier, in order to stay as concise as possible. In case of doubt, do not hesitate to go back to the chapter describing in details all configurable attributes.

22.1. General functions

These general functions should be used to initialize and configure the Yoctopuce library. In most cases, a simple call to function yRegisterHub() should be enough. The module-specific functions yFind...() or yFirst...() should then be used to retrieve an object that provides interaction with the module.

In order to use the functions described here, you should include:

js
<script type='text/javascript' src='yocto_api.js'></script>
nodejs
var yoctolib = require('yoctolib');
var YAPI = yoctolib.YAPI;
var YModule = yoctolib.YModule;
cpp
#include "yocto_api.h"
m
#import "yocto_api.h"
pas
uses yocto_api;
vb
yocto_api.vb
cs
yocto_api.cs
java
import com.yoctopuce.YoctoAPI.YModule;
py
from yocto_api import *
php
require_once('yocto_api.php');
es
import { YAPI, YErrorMsg, YModule } from 'yoctolib-es'
Global functions
yCheckLogicalName(name)

Checks if a given string is valid as logical name for a module or a function.

yDisableExceptions()

Disables the use of exceptions to report runtime errors.

yEnableExceptions()

Re-enables the use of exceptions for runtime error handling.

yEnableUSBHost(osContext)

This function is used only on Android.

yFreeAPI()

Frees dynamically allocated memory blocks used by the Yoctopuce library.

yGetAPIVersion()

Returns the version identifier for the Yoctopuce library in use.

yGetTickCount()

Returns the current value of a monotone millisecond-based time counter.

yHandleEvents(errmsg)

Maintains the device-to-library communication channel.

yInitAPI(mode, errmsg)

Initializes the Yoctopuce programming library explicitly.

yPreregisterHub(url, errmsg)

Fault-tolerant alternative to RegisterHub().

yRegisterDeviceArrivalCallback(arrivalCallback)

Register a callback function, to be called each time a device is plugged.

yRegisterDeviceRemovalCallback(removalCallback)

Register a callback function, to be called each time a device is unplugged.

yRegisterHub(url, errmsg)

Setup the Yoctopuce library to use modules connected on a given machine.

yRegisterHubDiscoveryCallback(hubDiscoveryCallback)

Register a callback function, to be called each time an Network Hub send an SSDP message.

yRegisterLogFunction(logfun)

Registers a log callback function.

ySelectArchitecture(arch)

Select the architecture or the library to be loaded to access to USB.

ySetDelegate(object)

(Objective-C only) Register an object that must follow the protocol YDeviceHotPlug.

ySetTimeout(callback, ms_timeout, args)

Invoke the specified callback function after a given timeout.

ySleep(ms_duration, errmsg)

Pauses the execution flow for a specified duration.

yTestHub(url, mstimeout, errmsg)

Test if the hub is reachable.

yTriggerHubDiscovery(errmsg)

Force a hub discovery, if a callback as been registered with yRegisterDeviceRemovalCallback it will be called for each net work hub that will respond to the discovery.

yUnregisterHub(url)

Setup the Yoctopuce library to no more use modules connected on a previously registered machine with RegisterHub.

yUpdateDeviceList(errmsg)

Triggers a (re)detection of connected Yoctopuce modules.

yUpdateDeviceList_async(callback, context)

Triggers a (re)detection of connected Yoctopuce modules.

YAPI.CheckLogicalName()
yCheckLogicalName()
yCheckLogicalName()YAPI.CheckLogicalName()yCheckLogicalName()[YAPI CheckLogicalName: ]yCheckLogicalName()yCheckLogicalName()YAPI.CheckLogicalName()YAPI.CheckLogicalName()YAPI.CheckLogicalName()yCheckLogicalName()YAPI.CheckLogicalName()

Checks if a given string is valid as logical name for a module or a function.

js
function yCheckLogicalName(name)
nodejs
function CheckLogicalName(name)
cpp
bool yCheckLogicalName(const string& name)
m
+(BOOL) CheckLogicalName:(NSString *) name
pas
function yCheckLogicalName(name: string): boolean
vb
function yCheckLogicalName(ByVal name As String) As Boolean
cs
bool CheckLogicalName(string name)
java
boolean CheckLogicalName(String name)
py
def CheckLogicalName(name)
php
function yCheckLogicalName($name)
es
function CheckLogicalName(name)

A valid logical name has a maximum of 19 characters, all among A..Z, a..z, 0..9, _, and -. If you try to configure a logical name with an incorrect string, the invalid characters are ignored.

Parameters :

namea string containing the name to check.

Returns :

true if the name is valid, false otherwise.

YAPI.DisableExceptions()
yDisableExceptions()
yDisableExceptions()YAPI.DisableExceptions()yDisableExceptions()[YAPI DisableExceptions]yDisableExceptions()yDisableExceptions()YAPI.DisableExceptions()YAPI.DisableExceptions()yDisableExceptions()YAPI.DisableExceptions()

Disables the use of exceptions to report runtime errors.

js
function yDisableExceptions()
nodejs
function DisableExceptions()
cpp
void yDisableExceptions()
m
+(void) DisableExceptions
pas
procedure yDisableExceptions()
vb
procedure yDisableExceptions()
cs
void DisableExceptions()
py
def DisableExceptions()
php
function yDisableExceptions()
es
function DisableExceptions()

When exceptions are disabled, every function returns a specific error value which depends on its type and which is documented in this reference manual.

YAPI.EnableExceptions()
yEnableExceptions()
yEnableExceptions()YAPI.EnableExceptions()yEnableExceptions()[YAPI EnableExceptions]yEnableExceptions()yEnableExceptions()YAPI.EnableExceptions()YAPI.EnableExceptions()yEnableExceptions()YAPI.EnableExceptions()

Re-enables the use of exceptions for runtime error handling.

js
function yEnableExceptions()
nodejs
function EnableExceptions()
cpp
void yEnableExceptions()
m
+(void) EnableExceptions
pas
procedure yEnableExceptions()
vb
procedure yEnableExceptions()
cs
void EnableExceptions()
py
def EnableExceptions()
php
function yEnableExceptions()
es
function EnableExceptions()

Be aware than when exceptions are enabled, every function that fails triggers an exception. If the exception is not caught by the user code, it either fires the debugger or aborts (i.e. crash) the program. On failure, throws an exception or returns a negative error code.

YAPI.EnableUSBHost()
yEnableUSBHost()
YAPI.EnableUSBHost()

This function is used only on Android.

java
void EnableUSBHost(Object osContext)

Before calling yRegisterHub("usb") you need to activate the USB host port of the system. This function takes as argument, an object of class android.content.Context (or any subclass). It is not necessary to call this function to reach modules through the network.

Parameters :

On failure, throws an exception.
osContextan object of class android.content.Context (or any subclass).

YAPI.FreeAPI()
yFreeAPI()
yFreeAPI()YAPI.FreeAPI()yFreeAPI()[YAPI FreeAPI]yFreeAPI()yFreeAPI()YAPI.FreeAPI()YAPI.FreeAPI()YAPI.FreeAPI()yFreeAPI()YAPI.FreeAPI()

Frees dynamically allocated memory blocks used by the Yoctopuce library.

js
function yFreeAPI()
nodejs
function FreeAPI()
cpp
void yFreeAPI()
m
+(void) FreeAPI
pas
procedure yFreeAPI()
vb
procedure yFreeAPI()
cs
void FreeAPI()
java
void FreeAPI()
py
def FreeAPI()
php
function yFreeAPI()
es
function FreeAPI()

It is generally not required to call this function, unless you want to free all dynamically allocated memory blocks in order to track a memory leak for instance. You should not call any other library function after calling yFreeAPI(), or your program will crash.

YAPI.GetAPIVersion()
yGetAPIVersion()
yGetAPIVersion()YAPI.GetAPIVersion()yGetAPIVersion()[YAPI GetAPIVersion]yGetAPIVersion()yGetAPIVersion()YAPI.GetAPIVersion()YAPI.GetAPIVersion()YAPI.GetAPIVersion()yGetAPIVersion()YAPI.GetAPIVersion()

Returns the version identifier for the Yoctopuce library in use.

js
function yGetAPIVersion()
nodejs
function GetAPIVersion()
cpp
string yGetAPIVersion()
m
+(NSString*) GetAPIVersion
pas
function yGetAPIVersion(): string
vb
function yGetAPIVersion() As String
cs
String GetAPIVersion()
java
String GetAPIVersion()
py
def GetAPIVersion()
php
function yGetAPIVersion()
es
function GetAPIVersion()

The version is a string in the form "Major.Minor.Build", for instance "1.01.5535". For languages using an external DLL (for instance C#, VisualBasic or Delphi), the character string includes as well the DLL version, for instance "1.01.5535 (1.01.5439)".

If you want to verify in your code that the library version is compatible with the version that you have used during development, verify that the major number is strictly equal and that the minor number is greater or equal. The build number is not relevant with respect to the library compatibility.

Returns :

a character string describing the library version.

YAPI.GetTickCount()
yGetTickCount()
yGetTickCount()YAPI.GetTickCount()yGetTickCount()[YAPI GetTickCount]yGetTickCount()yGetTickCount()YAPI.GetTickCount()YAPI.GetTickCount()YAPI.GetTickCount()yGetTickCount()YAPI.GetTickCount()

Returns the current value of a monotone millisecond-based time counter.

js
function yGetTickCount()
nodejs
function GetTickCount()
cpp
u64 yGetTickCount()
m
+(u64) GetTickCount
pas
function yGetTickCount(): u64
vb
function yGetTickCount() As Long
cs
ulong GetTickCount()
java
long GetTickCount()
py
def GetTickCount()
php
function yGetTickCount()
es
function GetTickCount()

This counter can be used to compute delays in relation with Yoctopuce devices, which also uses the millisecond as timebase.

Returns :

a long integer corresponding to the millisecond counter.

YAPI.HandleEvents()
yHandleEvents()
yHandleEvents()YAPI.HandleEvents()yHandleEvents()[YAPI HandleEvents: ]yHandleEvents()yHandleEvents()YAPI.HandleEvents()YAPI.HandleEvents()YAPI.HandleEvents()yHandleEvents()YAPI.HandleEvents()

Maintains the device-to-library communication channel.

js
function yHandleEvents(errmsg)
nodejs
function HandleEvents(errmsg)
cpp
YRETCODE yHandleEvents(string& errmsg)
m
+(YRETCODE) HandleEvents:(NSError**) errmsg
pas
function yHandleEvents(var errmsg: string): integer
vb
function yHandleEvents(ByRef errmsg As String) As YRETCODE
cs
YRETCODE HandleEvents(ref string errmsg)
java
int HandleEvents()
py
def HandleEvents(errmsg=None)
php
function yHandleEvents(&$errmsg)
es
function HandleEvents(errmsg)

If your program includes significant loops, you may want to include a call to this function to make sure that the library takes care of the information pushed by the modules on the communication channels. This is not strictly necessary, but it may improve the reactivity of the library for the following commands.

This function may signal an error in case there is a communication problem while contacting a module.

Parameters :

errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.InitAPI()
yInitAPI()
yInitAPI()YAPI.InitAPI()yInitAPI()[YAPI InitAPI: ]yInitAPI()yInitAPI()YAPI.InitAPI()YAPI.InitAPI()YAPI.InitAPI()yInitAPI()YAPI.InitAPI()

Initializes the Yoctopuce programming library explicitly.

js
function yInitAPI(mode, errmsg)
nodejs
function InitAPI(mode, errmsg)
cpp
YRETCODE yInitAPI(int mode, string& errmsg)
m
+(YRETCODE) InitAPI:(int) mode :(NSError**) errmsg
pas
function yInitAPI(mode: integer, var errmsg: string): integer
vb
function yInitAPI(ByVal mode As Integer, ByRef errmsg As String) As Integer
cs
int InitAPI(int mode, ref string errmsg)
java
int InitAPI(int mode)
py
def InitAPI(mode, errmsg=None)
php
function yInitAPI($mode, &$errmsg)
es
function InitAPI(mode, errmsg)

It is not strictly needed to call yInitAPI(), as the library is automatically initialized when calling yRegisterHub() for the first time.

When Y_DETECT_NONE is used as detection mode, you must explicitly use yRegisterHub() to point the API to the VirtualHub on which your devices are connected before trying to access them.

Parameters :

modean integer corresponding to the type of automatic device detection to use. Possible values are Y_DETECT_NONE, Y_DETECT_USB, Y_DETECT_NET, and Y_DETECT_ALL.
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.PreregisterHub()
yPreregisterHub()
yPreregisterHub()YAPI.PreregisterHub()yPreregisterHub()[YAPI PreregisterHub: ]yPreregisterHub()yPreregisterHub()YAPI.PreregisterHub()YAPI.PreregisterHub()YAPI.PreregisterHub()yPreregisterHub()YAPI.PreregisterHub()

Fault-tolerant alternative to RegisterHub().

js
function yPreregisterHub(url, errmsg)
nodejs
function PreregisterHub(url, errmsg)
cpp
YRETCODE yPreregisterHub(const string& url, string& errmsg)
m
+(YRETCODE) PreregisterHub:(NSString *) url :(NSError**) errmsg
pas
function yPreregisterHub(url: string, var errmsg: string): integer
vb
function yPreregisterHub(ByVal url As String,
  ByRef errmsg As String) As Integer
cs
int PreregisterHub(string url, ref string errmsg)
java
int PreregisterHub(String url)
py
def PreregisterHub(url, errmsg=None)
php
function yPreregisterHub($url, &$errmsg)
es
function PreregisterHub(url, errmsg)

This function has the same purpose and same arguments as RegisterHub(), but does not trigger an error when the selected hub is not available at the time of the function call. This makes it possible to register a network hub independently of the current connectivity, and to try to contact it only when a device is actively needed.

Parameters :

urla string containing either "usb","callback" or the root URL of the hub to monitor
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.RegisterDeviceArrivalCallback()
yRegisterDeviceArrivalCallback()
yRegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()[YAPI RegisterDeviceArrivalCallback: ]yRegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()

Register a callback function, to be called each time a device is plugged.

js
function yRegisterDeviceArrivalCallback(arrivalCallback)
nodejs
function RegisterDeviceArrivalCallback(arrivalCallback)
cpp
void yRegisterDeviceArrivalCallback(yDeviceUpdateCallback arrivalCallback)
m
+(void) RegisterDeviceArrivalCallback:(yDeviceUpdateCallback) arrivalCallback
pas
procedure yRegisterDeviceArrivalCallback(arrivalCallback: yDeviceUpdateFunc)
vb
procedure yRegisterDeviceArrivalCallback(ByVal arrivalCallback As yDeviceUpdateFunc)
cs
void RegisterDeviceArrivalCallback(yDeviceUpdateFunc arrivalCallback)
java
void RegisterDeviceArrivalCallback(DeviceArrivalCallback arrivalCallback)
py
def RegisterDeviceArrivalCallback(arrivalCallback)
php
function yRegisterDeviceArrivalCallback($arrivalCallback)
es
function RegisterDeviceArrivalCallback(arrivalCallback)

This callback will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered callback.
arrivalCallbacka procedure taking a YModule parameter, or null

YAPI.RegisterDeviceRemovalCallback()
yRegisterDeviceRemovalCallback()
yRegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()[YAPI RegisterDeviceRemovalCallback: ]yRegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()

Register a callback function, to be called each time a device is unplugged.

js
function yRegisterDeviceRemovalCallback(removalCallback)
nodejs
function RegisterDeviceRemovalCallback(removalCallback)
cpp
void yRegisterDeviceRemovalCallback(yDeviceUpdateCallback removalCallback)
m
+(void) RegisterDeviceRemovalCallback:(yDeviceUpdateCallback) removalCallback
pas
procedure yRegisterDeviceRemovalCallback(removalCallback: yDeviceUpdateFunc)
vb
procedure yRegisterDeviceRemovalCallback(ByVal removalCallback As yDeviceUpdateFunc)
cs
void RegisterDeviceRemovalCallback(yDeviceUpdateFunc removalCallback)
java
void RegisterDeviceRemovalCallback(DeviceRemovalCallback removalCallback)
py
def RegisterDeviceRemovalCallback(removalCallback)
php
function yRegisterDeviceRemovalCallback($removalCallback)
es
function RegisterDeviceRemovalCallback(removalCallback)

This callback will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered callback.
removalCallbacka procedure taking a YModule parameter, or null

YAPI.RegisterHub()
yRegisterHub()
yRegisterHub()YAPI.RegisterHub()yRegisterHub()[YAPI RegisterHub: ]yRegisterHub()yRegisterHub()YAPI.RegisterHub()YAPI.RegisterHub()YAPI.RegisterHub()yRegisterHub()YAPI.RegisterHub()

Setup the Yoctopuce library to use modules connected on a given machine.

js
function yRegisterHub(url, errmsg)
nodejs
function RegisterHub(url, errmsg)
cpp
YRETCODE yRegisterHub(const string& url, string& errmsg)
m
+(YRETCODE) RegisterHub:(NSString *) url :(NSError**) errmsg
pas
function yRegisterHub(url: string, var errmsg: string): integer
vb
function yRegisterHub(ByVal url As String,
  ByRef errmsg As String) As Integer
cs
int RegisterHub(string url, ref string errmsg)
java
int RegisterHub(String url)
py
def RegisterHub(url, errmsg=None)
php
function yRegisterHub($url, &$errmsg)
es
function RegisterHub(url, errmsg)

The parameter will determine how the API will work. Use the following values:

usb: When the usb keyword is used, the API will work with devices connected directly to the USB bus. Some programming languages such a Javascript, PHP, and Java don't provide direct access to USB hardware, so usb will not work with these. In this case, use a VirtualHub or a networked YoctoHub (see below).

x.x.x.x or hostname: The API will use the devices connected to the host with the given IP address or hostname. That host can be a regular computer running a VirtualHub, or a networked YoctoHub such as YoctoHub-Ethernet or YoctoHub-Wireless. If you want to use the VirtualHub running on you local computer, use the IP address 127.0.0.1.

callback: that keyword make the API run in "HTTP Callback" mode. This a special mode allowing to take control of Yoctopuce devices through a NAT filter when using a VirtualHub or a networked YoctoHub. You only need to configure your hub to call your server script on a regular basis. This mode is currently available for PHP and Node.JS only.

Be aware that only one application can use direct USB access at a given time on a machine. Multiple access would cause conflicts while trying to access the USB modules. In particular, this means that you must stop the VirtualHub software before starting an application that uses direct USB access. The workaround for this limitation is to setup the library to use the VirtualHub rather than direct USB access.

If access control has been activated on the hub, virtual or not, you want to reach, the URL parameter should look like:

http://username:password@address:port

You can call RegisterHub several times to connect to several machines.

Parameters :

urla string containing either "usb","callback" or the root URL of the hub to monitor
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.RegisterHubDiscoveryCallback()
yRegisterHubDiscoveryCallback()
yRegisterHubDiscoveryCallback()[YAPI RegisterHubDiscoveryCallback: ]yRegisterHubDiscoveryCallback()yRegisterHubDiscoveryCallback()YAPI.RegisterHubDiscoveryCallback()YAPI.RegisterHubDiscoveryCallback()YAPI.RegisterHubDiscoveryCallback()

Register a callback function, to be called each time an Network Hub send an SSDP message.

cpp
void yRegisterHubDiscoveryCallback(YHubDiscoveryCallback hubDiscoveryCallback)
m
+(void) RegisterHubDiscoveryCallback: (YHubDiscoveryCallback) hubDiscoveryCallback
pas
procedure yRegisterHubDiscoveryCallback(hubDiscoveryCallback: YHubDiscoveryCallback)
vb
procedure yRegisterHubDiscoveryCallback(ByVal hubDiscoveryCallback As YHubDiscoveryCallback)
cs
void RegisterHubDiscoveryCallback(YHubDiscoveryCallback hubDiscoveryCallback)
java
void RegisterHubDiscoveryCallback(HubDiscoveryCallback hubDiscoveryCallback)
py
def RegisterHubDiscoveryCallback(hubDiscoveryCallback)

The callback has two string parameter, the first one contain the serial number of the hub and the second contain the URL of the network hub (this URL can be passed to RegisterHub). This callback will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered callback.
hubDiscoveryCallbacka procedure taking two string parameter, or null

YAPI.RegisterLogFunction()
yRegisterLogFunction()
yRegisterLogFunction()[YAPI RegisterLogFunction: ]yRegisterLogFunction()yRegisterLogFunction()YAPI.RegisterLogFunction()YAPI.RegisterLogFunction()YAPI.RegisterLogFunction()

Registers a log callback function.

cpp
void yRegisterLogFunction(yLogFunction logfun)
m
+(void) RegisterLogFunction:(yLogCallback) logfun
pas
procedure yRegisterLogFunction(logfun: yLogFunc)
vb
procedure yRegisterLogFunction(ByVal logfun As yLogFunc)
cs
void RegisterLogFunction(yLogFunc logfun)
java
void RegisterLogFunction(LogCallback logfun)
py
def RegisterLogFunction(logfun)

This callback will be called each time the API have something to say. Quite useful to debug the API.

Parameters :

to unregister a previously registered callback.
logfuna procedure taking a string parameter, or null

YAPI.SelectArchitecture()
ySelectArchitecture()
YAPI.SelectArchitecture()

Select the architecture or the library to be loaded to access to USB.

py
def SelectArchitecture(arch)

By default, the Python library automatically detects the appropriate library to use. However, for Linux ARM, it not possible to reliably distinguish between a Hard Float (armhf) and a Soft Float (armel) install. For in this case, it is therefore recommended to manually select the proper architecture by calling SelectArchitecture() before any other call to the library.

Parameters :

archA string containing the architecture to use. Possibles value are: "armhf","armel", "i386","x86_64","32bit", "64bit"

Returns :

nothing.

On failure, throws an exception.

YAPI.SetDelegate()
ySetDelegate()
[YAPI SetDelegate: ]

(Objective-C only) Register an object that must follow the protocol YDeviceHotPlug.

m
+(void) SetDelegate:(id) object

The methods yDeviceArrival and yDeviceRemoval will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered object.
objectan object that must follow the protocol YAPIDelegate, or nil

YAPI.SetTimeout()
ySetTimeout()
ySetTimeout()YAPI.SetTimeout()YAPI.SetTimeout()

Invoke the specified callback function after a given timeout.

js
function ySetTimeout(callback, ms_timeout, args)
nodejs
function SetTimeout(callback, ms_timeout, arguments)
es
function SetTimeout(callback, ms_timeout, args)

This function behaves more or less like Javascript setTimeout, but during the waiting time, it will call yHandleEvents and yUpdateDeviceList periodically, in order to keep the API up-to-date with current devices.

Parameters :

callbackthe function to call after the timeout occurs. On Microsoft Internet Explorer, the callback must be provided as a string to be evaluated.
ms_timeoutan integer corresponding to the duration of the timeout, in milliseconds.
argsadditional arguments to be passed to the callback function can be provided, if needed (not supported on Microsoft Internet Explorer).

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.Sleep()
ySleep()
ySleep()YAPI.Sleep()ySleep()[YAPI Sleep: ]ySleep()ySleep()YAPI.Sleep()YAPI.Sleep()YAPI.Sleep()ySleep()YAPI.Sleep()

Pauses the execution flow for a specified duration.

js
function ySleep(ms_duration, errmsg)
nodejs
function Sleep(ms_duration, errmsg)
cpp
YRETCODE ySleep(unsigned ms_duration, string& errmsg)
m
+(YRETCODE) Sleep:(unsigned) ms_duration :(NSError **) errmsg
pas
function ySleep(ms_duration: integer, var errmsg: string): integer
vb
function ySleep(ByVal ms_duration As Integer,
  ByRef errmsg As String) As Integer
cs
int Sleep(int ms_duration, ref string errmsg)
java
int Sleep(long ms_duration)
py
def Sleep(ms_duration, errmsg=None)
php
function ySleep($ms_duration, &$errmsg)
es
function Sleep(ms_duration, errmsg)

This function implements a passive waiting loop, meaning that it does not consume CPU cycles significantly. The processor is left available for other threads and processes. During the pause, the library nevertheless reads from time to time information from the Yoctopuce modules by calling yHandleEvents(), in order to stay up-to-date.

This function may signal an error in case there is a communication problem while contacting a module.

Parameters :

ms_durationan integer corresponding to the duration of the pause, in milliseconds.
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.TestHub()
yTestHub()
yTestHub()[YAPI TestHub: ]yTestHub()yTestHub()YAPI.TestHub()YAPI.TestHub()YAPI.TestHub()yTestHub()

Test if the hub is reachable.

cpp
YRETCODE yTestHub(const string& url, int mstimeout, string& errmsg)
m
+(YRETCODE) TestHub: (NSString*) url
  : (int) mstimeout
  : (NSError**) errmsg
pas
function yTestHub(url: string,
  mstimeout: integer,
  var errmsg: string): integer
vb
function yTestHub(ByVal url As String,
  ByVal mstimeout As Integer,
  ByRef errmsg As String) As Integer
cs
int TestHub(string url, int mstimeout, ref string errmsg)
java
int TestHub(String url, int mstimeout)
py
def TestHub(url, mstimeout, errmsg=None)
php
function yTestHub($url, $mstimeout, &$errmsg)

This method do not register the hub, it only test if the hub is usable. The url parameter follow the same convention as the RegisterHub method. This method is useful to verify the authentication parameters for a hub. It is possible to force this method to return after mstimeout milliseconds.

Parameters :

urla string containing either "usb","callback" or the root URL of the hub to monitor
mstimeoutthe number of millisecond available to test the connection.
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure returns a negative error code.

YAPI.TriggerHubDiscovery()
yTriggerHubDiscovery()
yTriggerHubDiscovery()[YAPI TriggerHubDiscovery: ]yTriggerHubDiscovery()yTriggerHubDiscovery()YAPI.TriggerHubDiscovery()YAPI.TriggerHubDiscovery()YAPI.TriggerHubDiscovery()

Force a hub discovery, if a callback as been registered with yRegisterDeviceRemovalCallback it will be called for each net work hub that will respond to the discovery.

cpp
YRETCODE yTriggerHubDiscovery(string& errmsg)
m
+(YRETCODE) TriggerHubDiscovery: (NSError**) errmsg
pas
function yTriggerHubDiscovery(var errmsg: string): integer
vb
function yTriggerHubDiscovery(ByRef errmsg As String) As Integer
cs
int TriggerHubDiscovery(ref string errmsg)
java
int TriggerHubDiscovery()
py
def TriggerHubDiscovery(errmsg=None)

Parameters :

errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

YAPI.UnregisterHub()
yUnregisterHub()
yUnregisterHub()YAPI.UnregisterHub()yUnregisterHub()[YAPI UnregisterHub: ]yUnregisterHub()yUnregisterHub()YAPI.UnregisterHub()YAPI.UnregisterHub()YAPI.UnregisterHub()yUnregisterHub()YAPI.UnregisterHub()

Setup the Yoctopuce library to no more use modules connected on a previously registered machine with RegisterHub.

js
function yUnregisterHub(url)
nodejs
function UnregisterHub(url)
cpp
void yUnregisterHub(const string& url)
m
+(void) UnregisterHub:(NSString *) url
pas
procedure yUnregisterHub(url: string)
vb
procedure yUnregisterHub(ByVal url As String)
cs
void UnregisterHub(string url)
java
void UnregisterHub(String url)
py
def UnregisterHub(url)
php
function yUnregisterHub($url)
es
function UnregisterHub(url)

Parameters :

root URL of the hub to monitor
urla string containing either "usb" or the

YAPI.UpdateDeviceList()
yUpdateDeviceList()
yUpdateDeviceList()YAPI.UpdateDeviceList()yUpdateDeviceList()[YAPI UpdateDeviceList: ]yUpdateDeviceList()yUpdateDeviceList()YAPI.UpdateDeviceList()YAPI.UpdateDeviceList()YAPI.UpdateDeviceList()yUpdateDeviceList()YAPI.UpdateDeviceList()

Triggers a (re)detection of connected Yoctopuce modules.

js
function yUpdateDeviceList(errmsg)
nodejs
function UpdateDeviceList(errmsg)
cpp
YRETCODE yUpdateDeviceList(string& errmsg)
m
+(YRETCODE) UpdateDeviceList:(NSError**) errmsg
pas
function yUpdateDeviceList(var errmsg: string): integer
vb
function yUpdateDeviceList(ByRef errmsg As String) As YRETCODE
cs
YRETCODE UpdateDeviceList(ref string errmsg)
java
int UpdateDeviceList()
py
def UpdateDeviceList(errmsg=None)
php
function yUpdateDeviceList(&$errmsg)
es
function UpdateDeviceList(errmsg)

The library searches the machines or USB ports previously registered using yRegisterHub(), and invokes any user-defined callback function in case a change in the list of connected devices is detected.

This function can be called as frequently as desired to refresh the device list and to make the application aware of hot-plug events.

Parameters :

errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.UpdateDeviceList_async()
yUpdateDeviceList_async()
yUpdateDeviceList_async()YAPI.UpdateDeviceList_async()

Triggers a (re)detection of connected Yoctopuce modules.

js
function yUpdateDeviceList_async(callback, context)
nodejs
function UpdateDeviceList_async(callback, context)

The library searches the machines or USB ports previously registered using yRegisterHub(), and invokes any user-defined callback function in case a change in the list of connected devices is detected.

This function can be called as frequently as desired to refresh the device list and to make the application aware of hot-plug events.

This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox Javascript VM that does not implement context switching during blocking I/O calls.

Parameters :

callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the result code (YAPI_SUCCESS if the operation completes successfully) and the error message.
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

22.2. Module control interface

This interface is identical for all Yoctopuce USB modules. It can be used to control the module global parameters, and to enumerate the functions provided by each module.

In order to use the functions described here, you should include:

js
<script type='text/javascript' src='yocto_api.js'></script>
nodejs
var yoctolib = require('yoctolib');
var YAPI = yoctolib.YAPI;
var YModule = yoctolib.YModule;
cpp
#include "yocto_api.h"
m
#import "yocto_api.h"
pas
uses yocto_api;
vb
yocto_api.vb
cs
yocto_api.cs
java
import com.yoctopuce.YoctoAPI.YModule;
py
from yocto_api import *
php
require_once('yocto_api.php');
es
import { YAPI, YErrorMsg, YModule } from 'yoctolib-es'
Global functions
yFindModule(func)

Allows you to find a module from its serial number or from its logical name.

yFindModuleInContext(yctx, func)

Retrieves a module for a given identifier in a YAPI context.

yFirstModule()

Starts the enumeration of modules currently accessible.

YModule methods
module→checkFirmware(path, onlynew)

Tests whether the byn file is valid for this module.

module→clearCache()

Invalidates the cache.

module→describe()

Returns a descriptive text that identifies the module.

module→download(pathname)

Downloads the specified built-in file and returns a binary buffer with its content.

module→functionCount()

Returns the number of functions (beside the "module" interface) available on the module.

module→functionId(functionIndex)

Retrieves the hardware identifier of the nth function on the module.

module→functionName(functionIndex)

Retrieves the logical name of the nth function on the module.

module→functionType(functionIndex)

Retrieves the type of the nth function on the module.

module→functionValue(functionIndex)

Retrieves the advertised value of the nth function on the module.

module→get_allSettings()

Returns all the settings and uploaded files of the module.

module→get_beacon()

Returns the state of the localization beacon.

module→get_errorMessage()

Returns the error message of the latest error with this module object.

module→get_errorType()

Returns the numerical error code of the latest error with this module object.

module→get_firmwareRelease()

Returns the version of the firmware embedded in the module.

module→get_functionIds(funType)

Retrieve all hardware identifier that match the type passed in argument.

module→get_hardwareId()

Returns the unique hardware identifier of the module.

module→get_icon2d()

Returns the icon of the module.

module→get_lastLogs()

Returns a string with last logs of the module.

module→get_logicalName()

Returns the logical name of the module.

module→get_luminosity()

Returns the luminosity of the module informative leds (from 0 to 100).

module→get_parentHub()

Returns the serial number of the YoctoHub on which this module is connected.

module→get_persistentSettings()

Returns the current state of persistent module settings.

module→get_productId()

Returns the USB device identifier of the module.

module→get_productName()

Returns the commercial name of the module, as set by the factory.

module→get_productRelease()

Returns the hardware release version of the module.

module→get_rebootCountdown()

Returns the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled.

module→get_serialNumber()

Returns the serial number of the module, as set by the factory.

module→get_subDevices()

Returns a list of all the modules that are plugged into the current module.

module→get_upTime()

Returns the number of milliseconds spent since the module was powered on.

module→get_url()

Returns the URL used to access the module.

module→get_usbCurrent()

Returns the current consumed by the module on the USB bus, in milli-amps.

module→get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

module→get_userVar()

Returns the value previously stored in this attribute.

module→hasFunction(funcId)

Tests if the device includes a specific function.

module→isOnline()

Checks if the module is currently reachable, without raising any error.

module→isOnline_async(callback, context)

Checks if the module is currently reachable, without raising any error.

module→load(msValidity)

Preloads the module cache with a specified validity duration.

module→load_async(msValidity, callback, context)

Preloads the module cache with a specified validity duration (asynchronous version).

module→log(text)

Adds a text message to the device logs.

module→nextModule()

Continues the module enumeration started using yFirstModule().

module→reboot(secBeforeReboot)

Schedules a simple module reboot after the given number of seconds.

module→registerLogCallback(callback)

Registers a device log callback function.

module→revertFromFlash()

Reloads the settings stored in the nonvolatile memory, as when the module is powered on.

module→saveToFlash()

Saves current settings in the nonvolatile memory of the module.

module→set_allSettings(settings)

Restores all the settings of the device.

module→set_allSettingsAndFiles(settings)

Restores all the settings and uploaded files to the module.

module→set_beacon(newval)

Turns on or off the module localization beacon.

module→set_logicalName(newval)

Changes the logical name of the module.

module→set_luminosity(newval)

Changes the luminosity of the module informative leds.

module→set_userData(data)

Stores a user context provided as argument in the userData attribute of the function.

module→set_userVar(newval)

Returns the value previously stored in this attribute.

module→triggerFirmwareUpdate(secBeforeReboot)

Schedules a module reboot into special firmware update mode.

module→updateFirmware(path)

Prepares a firmware update of the module.

module→updateFirmwareEx(path, force)

Prepares a firmware update of the module.

module→wait_async(callback, context)

Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.

YModule.FindModule()
yFindModule()
yFindModule()YModule.FindModule()yFindModule()[YModule FindModule: ]yFindModule()yFindModule()YModule.FindModule()YModule.FindModule()YModule.FindModule()yFindModule()YModule.FindModule()

Allows you to find a module from its serial number or from its logical name.

js
function yFindModule(func)
nodejs
function FindModule(func)
cpp
YModule* yFindModule(string func)
m
+(YModule*) FindModule: (NSString*) func
pas
function yFindModule(func: string): TYModule
vb
function yFindModule(ByVal func As String) As YModule
cs
YModule FindModule(string func)
java
YModule FindModule(String func)
py
def FindModule(func)
php
function yFindModule($func)
es
function FindModule(func)

This function does not require that the module is online at the time it is invoked. The returned object is nevertheless valid. Use the method YModule.isOnline() to test if the module is indeed online at a given time. In case of ambiguity when looking for a module by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.

Parameters :

funca string containing either the serial number or the logical name of the desired module

Returns :

a YModule object allowing you to drive the module or get additional information on the module.

YModule.FindModuleInContext()
yFindModuleInContext()
YModule.FindModuleInContext()YModule.FindModuleInContext()

Retrieves a module for a given identifier in a YAPI context.

java
YModule FindModuleInContext(YAPIContext yctx, String func)
es
function FindModuleInContext(yctx, func)

The identifier can be specified using several formats:

This function does not require that the module is online at the time it is invoked. The returned object is nevertheless valid. Use the method YModule.isOnline() to test if the module is indeed online at a given time. In case of ambiguity when looking for a module by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.

Parameters :

yctxa YAPI context
funca string that uniquely characterizes the module

Returns :

a YModule object allowing you to drive the module.

YModule.FirstModule()
yFirstModule()
yFirstModule()YModule.FirstModule()yFirstModule()[YModule FirstModule]yFirstModule()yFirstModule()YModule.FirstModule()YModule.FirstModule()YModule.FirstModule()yFirstModule()YModule.FirstModule()

Starts the enumeration of modules currently accessible.

js
function yFirstModule()
nodejs
function FirstModule()
cpp
YModule* yFirstModule()
m
+(YModule*) FirstModule
pas
function yFirstModule(): TYModule
vb
function yFirstModule() As YModule
cs
YModule FirstModule()
java
YModule FirstModule()
py
def FirstModule()
php
function yFirstModule()
es
function FirstModule()

Use the method YModule.nextModule() to iterate on the next modules.

Returns :

a pointer to a YModule object, corresponding to the first module currently online, or a null pointer if there are none.

module→checkFirmware()module.checkFirmware()module.checkFirmware()module→checkFirmware()[module checkFirmware: ]module.checkFirmware()module.checkFirmware()module.checkFirmware()module.checkFirmware()module.checkFirmware()module→checkFirmware()module.checkFirmware()YModule checkFirmware

Tests whether the byn file is valid for this module.

js
function checkFirmware(path, onlynew)
nodejs
function checkFirmware(path, onlynew)
cpp
string checkFirmware(string path, bool onlynew)
m
-(NSString*) checkFirmware: (NSString*) path
  : (bool) onlynew
pas
function checkFirmware(path: string, onlynew: boolean): string
vb
function checkFirmware() As String
cs
string checkFirmware(string path, bool onlynew)
java
String checkFirmware(String path, boolean onlynew)
py
def checkFirmware(path, onlynew)
php
function checkFirmware($path, $onlynew)
es
function checkFirmware(path, onlynew)
cmd
YModule target checkFirmware path onlynew

This method is useful to test if the module needs to be updated. It is possible to pass a directory as argument instead of a file. In this case, this method returns the path of the most recent appropriate .byn file. If the parameter onlynew is true, the function discards firmwares that are older or equal to the installed firmware.

Parameters :

paththe path of a byn file or a directory that contains byn files
onlynewreturns only files that are strictly newer

Returns :

the path of the byn file to use or a empty string if no byn files matches the requirement

On failure, throws an exception or returns a string that start with "error:".

module→clearCache()module.clearCache()module.clearCache()module→clearCache()[module clearCache]module.clearCache()module.clearCache()module.clearCache()module.clearCache()module.clearCache()module→clearCache()module.clearCache()

Invalidates the cache.

js
function clearCache()
nodejs
function clearCache()
cpp
void clearCache()
m
-(void) clearCache
pas
procedure clearCache()
vb
procedure clearCache()
cs
void clearCache()
java
void clearCache()
py
def clearCache()
php
function clearCache()
es
function clearCache()

Invalidates the cache of the module attributes. Forces the next call to get_xxx() or loadxxx() to use values that come from the device.

module→describe()module.describe()module.describe()module→describe()[module describe]module.describe()module.describe()module.describe()module.describe()module.describe()module→describe()module.describe()

Returns a descriptive text that identifies the module.

js
function describe()
nodejs
function describe()
cpp
string describe()
m
-(NSString*) describe
pas
function describe(): string
vb
function describe() As String
cs
string describe()
java
String describe()
py
def describe()
php
function describe()
es
function describe()

The text may include either the logical name or the serial number of the module.

Returns :

a string that describes the module

module→download()module.download()module.download()module→download()[module download: ]module.download()module.download()module.download()module.download()module.download()module→download()module.download()YModule download

Downloads the specified built-in file and returns a binary buffer with its content.

js
function download(pathname)
nodejs
function download(pathname)
cpp
string download(string pathname)
m
-(NSMutableData*) download: (NSString*) pathname
pas
function download(pathname: string): TByteArray
vb
function download() As Byte
cs
byte[] download(string pathname)
java
byte[] download(String pathname)
py
def download(pathname)
php
function download($pathname)
es
function download(pathname)
cmd
YModule target download pathname

Parameters :

pathnamename of the new file to load

Returns :

a binary buffer with the file content

On failure, throws an exception or returns YAPI_INVALID_STRING.

module→functionCount()module.functionCount()module.functionCount()module→functionCount()[module functionCount]module.functionCount()module.functionCount()module.functionCount()module.functionCount()module.functionCount()module→functionCount()module.functionCount()

Returns the number of functions (beside the "module" interface) available on the module.

js
function functionCount()
nodejs
function functionCount()
cpp
int functionCount()
m
-(int) functionCount
pas
function functionCount(): integer
vb
function functionCount() As Integer
cs
int functionCount()
java
int functionCount()
py
def functionCount()
php
function functionCount()
es
function functionCount()

Returns :

the number of functions on the module

On failure, throws an exception or returns a negative error code.

module→functionId()module.functionId()module.functionId()module→functionId()[module functionId: ]module.functionId()module.functionId()module.functionId()module.functionId()module.functionId()module→functionId()module.functionId()

Retrieves the hardware identifier of the nth function on the module.

js
function functionId(functionIndex)
nodejs
function functionId(functionIndex)
cpp
string functionId(int functionIndex)
m
-(NSString*) functionId: (int) functionIndex
pas
function functionId(functionIndex: integer): string
vb
function functionId(ByVal functionIndex As Integer) As String
cs
string functionId(int functionIndex)
java
String functionId(int functionIndex)
py
def functionId(functionIndex)
php
function functionId($functionIndex)
es
function functionId(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a string corresponding to the unambiguous hardware identifier of the requested module function

On failure, throws an exception or returns an empty string.

module→functionName()module.functionName()module.functionName()module→functionName()[module functionName: ]module.functionName()module.functionName()module.functionName()module.functionName()module.functionName()module→functionName()module.functionName()

Retrieves the logical name of the nth function on the module.

js
function functionName(functionIndex)
nodejs
function functionName(functionIndex)
cpp
string functionName(int functionIndex)
m
-(NSString*) functionName: (int) functionIndex
pas
function functionName(functionIndex: integer): string
vb
function functionName(ByVal functionIndex As Integer) As String
cs
string functionName(int functionIndex)
java
String functionName(int functionIndex)
py
def functionName(functionIndex)
php
function functionName($functionIndex)
es
function functionName(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a string corresponding to the logical name of the requested module function

On failure, throws an exception or returns an empty string.

module→functionType()module.functionType()module.functionType()module→functionType()module.functionType()module.functionType()module.functionType()module.functionType()module.functionType()module→functionType()module.functionType()

Retrieves the type of the nth function on the module.

js
function functionType(functionIndex)
nodejs
function functionType(functionIndex)
cpp
string functionType(int functionIndex)
pas
function functionType(functionIndex: integer): string
vb
function functionType(ByVal functionIndex As Integer) As String
cs
string functionType(int functionIndex)
java
String functionType(int functionIndex)
py
def functionType(functionIndex)
php
function functionType($functionIndex)
es
function functionType(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a the type of the function

On failure, throws an exception or returns an empty string.

module→functionValue()module.functionValue()module.functionValue()module→functionValue()[module functionValue: ]module.functionValue()module.functionValue()module.functionValue()module.functionValue()module.functionValue()module→functionValue()module.functionValue()

Retrieves the advertised value of the nth function on the module.

js
function functionValue(functionIndex)
nodejs
function functionValue(functionIndex)
cpp
string functionValue(int functionIndex)
m
-(NSString*) functionValue: (int) functionIndex
pas
function functionValue(functionIndex: integer): string
vb
function functionValue(ByVal functionIndex As Integer) As String
cs
string functionValue(int functionIndex)
java
String functionValue(int functionIndex)
py
def functionValue(functionIndex)
php
function functionValue($functionIndex)
es
function functionValue(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a short string (up to 6 characters) corresponding to the advertised value of the requested module function

On failure, throws an exception or returns an empty string.

module→get_allSettings()
module→allSettings()
module.get_allSettings()module.get_allSettings()module→get_allSettings()[module allSettings]module.get_allSettings()module.get_allSettings()module.get_allSettings()module.get_allSettings()module.get_allSettings()module→get_allSettings()module.get_allSettings()YModule get_allSettings

Returns all the settings and uploaded files of the module.

js
function get_allSettings()
nodejs
function get_allSettings()
cpp
string get_allSettings()
m
-(NSMutableData*) allSettings
pas
function get_allSettings(): TByteArray
vb
function get_allSettings() As Byte
cs
byte[] get_allSettings()
java
byte[] get_allSettings()
py
def get_allSettings()
php
function get_allSettings()
es
function get_allSettings()
cmd
YModule target get_allSettings

Useful to backup all the logical names, calibrations parameters, and uploaded files of a device.

Returns :

a binary buffer with all the settings.

On failure, throws an exception or returns an binary object of size 0.

module→get_beacon()
module→beacon()
module.get_beacon()module.get_beacon()module→get_beacon()[module beacon]module.get_beacon()module.get_beacon()module.get_beacon()module.get_beacon()module.get_beacon()module→get_beacon()module.get_beacon()YModule get_beacon

Returns the state of the localization beacon.

js
function get_beacon()
nodejs
function get_beacon()
cpp
Y_BEACON_enum get_beacon()
m
-(Y_BEACON_enum) beacon
pas
function get_beacon(): Integer
vb
function get_beacon() As Integer
cs
int get_beacon()
java
int get_beacon()
py
def get_beacon()
php
function get_beacon()
es
function get_beacon()
cmd
YModule target get_beacon

Returns :

either Y_BEACON_OFF or Y_BEACON_ON, according to the state of the localization beacon

On failure, throws an exception or returns Y_BEACON_INVALID.

module→get_errorMessage()
module→errorMessage()
module.get_errorMessage()module.get_errorMessage()module→get_errorMessage()[module errorMessage]module.get_errorMessage()module.get_errorMessage()module.get_errorMessage()module.get_errorMessage()module.get_errorMessage()module→get_errorMessage()module.get_errorMessage()

Returns the error message of the latest error with this module object.

js
function get_errorMessage()
nodejs
function get_errorMessage()
cpp
string get_errorMessage()
m
-(NSString*) errorMessage
pas
function get_errorMessage(): string
vb
function get_errorMessage() As String
cs
string get_errorMessage()
java
String get_errorMessage()
py
def get_errorMessage()
php
function get_errorMessage()
es
function get_errorMessage()

This method is mostly useful when using the Yoctopuce library with exceptions disabled.

Returns :

a string corresponding to the latest error message that occured while using this module object

module→get_errorType()
module→errorType()
module.get_errorType()module.get_errorType()module→get_errorType()module.get_errorType()module.get_errorType()module.get_errorType()module.get_errorType()module.get_errorType()module→get_errorType()module.get_errorType()

Returns the numerical error code of the latest error with this module object.

js
function get_errorType()
nodejs
function get_errorType()
cpp
YRETCODE get_errorType()
pas
function get_errorType(): YRETCODE
vb
function get_errorType() As YRETCODE
cs
YRETCODE get_errorType()
java
int get_errorType()
py
def get_errorType()
php
function get_errorType()
es
function get_errorType()

This method is mostly useful when using the Yoctopuce library with exceptions disabled.

Returns :

a number corresponding to the code of the latest error that occurred while using this module object

module→get_firmwareRelease()
module→firmwareRelease()
module.get_firmwareRelease()module.get_firmwareRelease()module→get_firmwareRelease()[module firmwareRelease]module.get_firmwareRelease()module.get_firmwareRelease()module.get_firmwareRelease()module.get_firmwareRelease()module.get_firmwareRelease()module→get_firmwareRelease()module.get_firmwareRelease()YModule get_firmwareRelease

Returns the version of the firmware embedded in the module.

js
function get_firmwareRelease()
nodejs
function get_firmwareRelease()
cpp
string get_firmwareRelease()
m
-(NSString*) firmwareRelease
pas
function get_firmwareRelease(): string
vb
function get_firmwareRelease() As String
cs
string get_firmwareRelease()
java
String get_firmwareRelease()
py
def get_firmwareRelease()
php
function get_firmwareRelease()
es
function get_firmwareRelease()
cmd
YModule target get_firmwareRelease

Returns :

a string corresponding to the version of the firmware embedded in the module

On failure, throws an exception or returns Y_FIRMWARERELEASE_INVALID.

module→get_functionIds()
module→functionIds()
module.get_functionIds()module.get_functionIds()module→get_functionIds()[module functionIds: ]module.get_functionIds()module.get_functionIds()module.get_functionIds()module.get_functionIds()module.get_functionIds()module→get_functionIds()module.get_functionIds()YModule get_functionIds

Retrieve all hardware identifier that match the type passed in argument.

js
function get_functionIds(funType)
nodejs
function get_functionIds(funType)
cpp
vector<string> get_functionIds(string funType)
m
-(NSMutableArray*) functionIds: (NSString*) funType
pas
function get_functionIds(funType: string): TStringArray
vb
function get_functionIds() As List
cs
List<string> get_functionIds(string funType)
java
ArrayList<String> get_functionIds(String funType)
py
def get_functionIds(funType)
php
function get_functionIds($funType)
es
function get_functionIds(funType)
cmd
YModule target get_functionIds funType

Parameters :

funTypeThe type of function (Relay, LightSensor, Voltage,...)

Returns :

an array of strings.

module→get_hardwareId()
module→hardwareId()
module.get_hardwareId()module.get_hardwareId()module→get_hardwareId()[module hardwareId]module.get_hardwareId()module.get_hardwareId()module.get_hardwareId()module.get_hardwareId()module→get_hardwareId()module.get_hardwareId()

Returns the unique hardware identifier of the module.

js
function get_hardwareId()
nodejs
function get_hardwareId()
cpp
string get_hardwareId()
m
-(NSString*) hardwareId
vb
function get_hardwareId() As String
cs
string get_hardwareId()
java
String get_hardwareId()
py
def get_hardwareId()
php
function get_hardwareId()
es
function get_hardwareId()

The unique hardware identifier is made of the device serial number followed by string ".module".

Returns :

a string that uniquely identifies the module

module→get_icon2d()
module→icon2d()
module.get_icon2d()module.get_icon2d()module→get_icon2d()[module icon2d]module.get_icon2d()module.get_icon2d()module.get_icon2d()module.get_icon2d()module.get_icon2d()module→get_icon2d()module.get_icon2d()YModule get_icon2d

Returns the icon of the module.

js
function get_icon2d()
nodejs
function get_icon2d()
cpp
string get_icon2d()
m
-(NSMutableData*) icon2d
pas
function get_icon2d(): TByteArray
vb
function get_icon2d() As Byte
cs
byte[] get_icon2d()
java
byte[] get_icon2d()
py
def get_icon2d()
php
function get_icon2d()
es
function get_icon2d()
cmd
YModule target get_icon2d

The icon is a PNG image and does not exceeds 1536 bytes.

Returns :

a binary buffer with module icon, in png format. On failure, throws an exception or returns YAPI_INVALID_STRING.

module→get_lastLogs()
module→lastLogs()
module.get_lastLogs()module.get_lastLogs()module→get_lastLogs()[module lastLogs]module.get_lastLogs()module.get_lastLogs()module.get_lastLogs()module.get_lastLogs()module.get_lastLogs()module→get_lastLogs()module.get_lastLogs()YModule get_lastLogs

Returns a string with last logs of the module.

js
function get_lastLogs()
nodejs
function get_lastLogs()
cpp
string get_lastLogs()
m
-(NSString*) lastLogs
pas
function get_lastLogs(): string
vb
function get_lastLogs() As String
cs
string get_lastLogs()
java
String get_lastLogs()
py
def get_lastLogs()
php
function get_lastLogs()
es
function get_lastLogs()
cmd
YModule target get_lastLogs

This method return only logs that are still in the module.

Returns :

a string with last logs of the module. On failure, throws an exception or returns YAPI_INVALID_STRING.

module→get_logicalName()
module→logicalName()
module.get_logicalName()module.get_logicalName()module→get_logicalName()[module logicalName]module.get_logicalName()module.get_logicalName()module.get_logicalName()module.get_logicalName()module.get_logicalName()module→get_logicalName()module.get_logicalName()YModule get_logicalName

Returns the logical name of the module.

js
function get_logicalName()
nodejs
function get_logicalName()
cpp
string get_logicalName()
m
-(NSString*) logicalName
pas
function get_logicalName(): string
vb
function get_logicalName() As String
cs
string get_logicalName()
java
String get_logicalName()
py
def get_logicalName()
php
function get_logicalName()
es
function get_logicalName()
cmd
YModule target get_logicalName

Returns :

a string corresponding to the logical name of the module

On failure, throws an exception or returns Y_LOGICALNAME_INVALID.

module→get_luminosity()
module→luminosity()
module.get_luminosity()module.get_luminosity()module→get_luminosity()[module luminosity]module.get_luminosity()module.get_luminosity()module.get_luminosity()module.get_luminosity()module.get_luminosity()module→get_luminosity()module.get_luminosity()YModule get_luminosity

Returns the luminosity of the module informative leds (from 0 to 100).

js
function get_luminosity()
nodejs
function get_luminosity()
cpp
int get_luminosity()
m
-(int) luminosity
pas
function get_luminosity(): LongInt
vb
function get_luminosity() As Integer
cs
int get_luminosity()
java
int get_luminosity()
py
def get_luminosity()
php
function get_luminosity()
es
function get_luminosity()
cmd
YModule target get_luminosity

Returns :

an integer corresponding to the luminosity of the module informative leds (from 0 to 100)

On failure, throws an exception or returns Y_LUMINOSITY_INVALID.

module→get_parentHub()
module→parentHub()
module.get_parentHub()module.get_parentHub()module→get_parentHub()[module parentHub]module.get_parentHub()module.get_parentHub()module.get_parentHub()module.get_parentHub()module.get_parentHub()module→get_parentHub()YModule get_parentHub

Returns the serial number of the YoctoHub on which this module is connected.

js
function get_parentHub()
nodejs
function get_parentHub()
cpp
string get_parentHub()
m
-(NSString*) parentHub
pas
function get_parentHub(): string
vb
function get_parentHub() As String
cs
string get_parentHub()
java
String get_parentHub()
py
def get_parentHub()
php
function get_parentHub()
cmd
YModule target get_parentHub

If the module is connected by USB, or if the module is the root YoctoHub, an empty string is returned.

Returns :

a string with the serial number of the YoctoHub or an empty string

module→get_persistentSettings()
module→persistentSettings()
module.get_persistentSettings()module.get_persistentSettings()module→get_persistentSettings()[module persistentSettings]module.get_persistentSettings()module.get_persistentSettings()module.get_persistentSettings()module.get_persistentSettings()module.get_persistentSettings()module→get_persistentSettings()module.get_persistentSettings()YModule get_persistentSettings

Returns the current state of persistent module settings.

js
function get_persistentSettings()
nodejs
function get_persistentSettings()
cpp
Y_PERSISTENTSETTINGS_enum get_persistentSettings()
m
-(Y_PERSISTENTSETTINGS_enum) persistentSettings
pas
function get_persistentSettings(): Integer
vb
function get_persistentSettings() As Integer
cs
int get_persistentSettings()
java
int get_persistentSettings()
py
def get_persistentSettings()
php
function get_persistentSettings()
es
function get_persistentSettings()
cmd
YModule target get_persistentSettings

Returns :

a value among Y_PERSISTENTSETTINGS_LOADED, Y_PERSISTENTSETTINGS_SAVED and Y_PERSISTENTSETTINGS_MODIFIED corresponding to the current state of persistent module settings

On failure, throws an exception or returns Y_PERSISTENTSETTINGS_INVALID.

module→get_productId()
module→productId()
module.get_productId()module.get_productId()module→get_productId()[module productId]module.get_productId()module.get_productId()module.get_productId()module.get_productId()module.get_productId()module→get_productId()module.get_productId()YModule get_productId

Returns the USB device identifier of the module.

js
function get_productId()
nodejs
function get_productId()
cpp
int get_productId()
m
-(int) productId
pas
function get_productId(): LongInt
vb
function get_productId() As Integer
cs
int get_productId()
java
int get_productId()
py
def get_productId()
php
function get_productId()
es
function get_productId()
cmd
YModule target get_productId

Returns :

an integer corresponding to the USB device identifier of the module

On failure, throws an exception or returns Y_PRODUCTID_INVALID.

module→get_productName()
module→productName()
module.get_productName()module.get_productName()module→get_productName()[module productName]module.get_productName()module.get_productName()module.get_productName()module.get_productName()module.get_productName()module→get_productName()module.get_productName()YModule get_productName

Returns the commercial name of the module, as set by the factory.

js
function get_productName()
nodejs
function get_productName()
cpp
string get_productName()
m
-(NSString*) productName
pas
function get_productName(): string
vb
function get_productName() As String
cs
string get_productName()
java
String get_productName()
py
def get_productName()
php
function get_productName()
es
function get_productName()
cmd
YModule target get_productName

Returns :

a string corresponding to the commercial name of the module, as set by the factory

On failure, throws an exception or returns Y_PRODUCTNAME_INVALID.

module→get_productRelease()
module→productRelease()
module.get_productRelease()module.get_productRelease()module→get_productRelease()[module productRelease]module.get_productRelease()module.get_productRelease()module.get_productRelease()module.get_productRelease()module.get_productRelease()module→get_productRelease()module.get_productRelease()YModule get_productRelease

Returns the hardware release version of the module.

js
function get_productRelease()
nodejs
function get_productRelease()
cpp
int get_productRelease()
m
-(int) productRelease
pas
function get_productRelease(): LongInt
vb
function get_productRelease() As Integer
cs
int get_productRelease()
java
int get_productRelease()
py
def get_productRelease()
php
function get_productRelease()
es
function get_productRelease()
cmd
YModule target get_productRelease

Returns :

an integer corresponding to the hardware release version of the module

On failure, throws an exception or returns Y_PRODUCTRELEASE_INVALID.

module→get_rebootCountdown()
module→rebootCountdown()
module.get_rebootCountdown()module.get_rebootCountdown()module→get_rebootCountdown()[module rebootCountdown]module.get_rebootCountdown()module.get_rebootCountdown()module.get_rebootCountdown()module.get_rebootCountdown()module.get_rebootCountdown()module→get_rebootCountdown()module.get_rebootCountdown()YModule get_rebootCountdown

Returns the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled.

js
function get_rebootCountdown()
nodejs
function get_rebootCountdown()
cpp
int get_rebootCountdown()
m
-(int) rebootCountdown
pas
function get_rebootCountdown(): LongInt
vb
function get_rebootCountdown() As Integer
cs
int get_rebootCountdown()
java
int get_rebootCountdown()
py
def get_rebootCountdown()
php
function get_rebootCountdown()
es
function get_rebootCountdown()
cmd
YModule target get_rebootCountdown

Returns :

an integer corresponding to the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled

On failure, throws an exception or returns Y_REBOOTCOUNTDOWN_INVALID.

module→get_serialNumber()
module→serialNumber()
module.get_serialNumber()module.get_serialNumber()module→get_serialNumber()[module serialNumber]module.get_serialNumber()module.get_serialNumber()module.get_serialNumber()module.get_serialNumber()module.get_serialNumber()module→get_serialNumber()module.get_serialNumber()YModule get_serialNumber

Returns the serial number of the module, as set by the factory.

js
function get_serialNumber()
nodejs
function get_serialNumber()
cpp
string get_serialNumber()
m
-(NSString*) serialNumber
pas
function get_serialNumber(): string
vb
function get_serialNumber() As String
cs
string get_serialNumber()
java
String get_serialNumber()
py
def get_serialNumber()
php
function get_serialNumber()
es
function get_serialNumber()
cmd
YModule target get_serialNumber

Returns :

a string corresponding to the serial number of the module, as set by the factory

On failure, throws an exception or returns Y_SERIALNUMBER_INVALID.

module→get_subDevices()
module→subDevices()
module.get_subDevices()module.get_subDevices()module→get_subDevices()[module subDevices]module.get_subDevices()module.get_subDevices()module.get_subDevices()module.get_subDevices()module.get_subDevices()module→get_subDevices()YModule get_subDevices

Returns a list of all the modules that are plugged into the current module.

js
function get_subDevices()
nodejs
function get_subDevices()
cpp
vector<string> get_subDevices()
m
-(NSMutableArray*) subDevices
pas
function get_subDevices(): TStringArray
vb
function get_subDevices() As List
cs
List<string> get_subDevices()
java
ArrayList<String> get_subDevices()
py
def get_subDevices()
php
function get_subDevices()
cmd
YModule target get_subDevices

This method only makes sense when called for a YoctoHub/VirtualHub. Otherwise, an empty array will be returned.

Returns :

an array of strings containing the sub modules.

module→get_upTime()
module→upTime()
module.get_upTime()module.get_upTime()module→get_upTime()[module upTime]module.get_upTime()module.get_upTime()module.get_upTime()module.get_upTime()module.get_upTime()module→get_upTime()module.get_upTime()YModule get_upTime

Returns the number of milliseconds spent since the module was powered on.

js
function get_upTime()
nodejs
function get_upTime()
cpp
s64 get_upTime()
m
-(s64) upTime
pas
function get_upTime(): int64
vb
function get_upTime() As Long
cs
long get_upTime()
java
long get_upTime()
py
def get_upTime()
php
function get_upTime()
es
function get_upTime()
cmd
YModule target get_upTime

Returns :

an integer corresponding to the number of milliseconds spent since the module was powered on

On failure, throws an exception or returns Y_UPTIME_INVALID.

module→get_url()
module→url()
module.get_url()module.get_url()module→get_url()[module url]module.get_url()module.get_url()module.get_url()module.get_url()module.get_url()module→get_url()YModule get_url

Returns the URL used to access the module.

js
function get_url()
nodejs
function get_url()
cpp
string get_url()
m
-(NSString*) url
pas
function get_url(): string
vb
function get_url() As String
cs
string get_url()
java
String get_url()
py
def get_url()
php
function get_url()
cmd
YModule target get_url

If the module is connected by USB, the string 'usb' is returned.

Returns :

a string with the URL of the module.

module→get_usbCurrent()
module→usbCurrent()
module.get_usbCurrent()module.get_usbCurrent()module→get_usbCurrent()[module usbCurrent]module.get_usbCurrent()module.get_usbCurrent()module.get_usbCurrent()module.get_usbCurrent()module.get_usbCurrent()module→get_usbCurrent()module.get_usbCurrent()YModule get_usbCurrent

Returns the current consumed by the module on the USB bus, in milli-amps.

js
function get_usbCurrent()
nodejs
function get_usbCurrent()
cpp
int get_usbCurrent()
m
-(int) usbCurrent
pas
function get_usbCurrent(): LongInt
vb
function get_usbCurrent() As Integer
cs
int get_usbCurrent()
java
int get_usbCurrent()
py
def get_usbCurrent()
php
function get_usbCurrent()
es
function get_usbCurrent()
cmd
YModule target get_usbCurrent

Returns :

an integer corresponding to the current consumed by the module on the USB bus, in milli-amps

On failure, throws an exception or returns Y_USBCURRENT_INVALID.

module→get_userData()
module→userData()
module.get_userData()module.get_userData()module→get_userData()[module userData]module.get_userData()module.get_userData()module.get_userData()module.get_userData()module.get_userData()module→get_userData()module.get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

js
function get_userData()
nodejs
function get_userData()
cpp
void * get_userData()
m
-(id) userData
pas
function get_userData(): Tobject
vb
function get_userData() As Object
cs
object get_userData()
java
Object get_userData()
py
def get_userData()
php
function get_userData()
es
function get_userData()

This attribute is never touched directly by the API, and is at disposal of the caller to store a context.

Returns :

the object stored previously by the caller.

module→get_userVar()
module→userVar()
module.get_userVar()module.get_userVar()module→get_userVar()[module userVar]module.get_userVar()module.get_userVar()module.get_userVar()module.get_userVar()module.get_userVar()module→get_userVar()module.get_userVar()YModule get_userVar

Returns the value previously stored in this attribute.

js
function get_userVar()
nodejs
function get_userVar()
cpp
int get_userVar()
m
-(int) userVar
pas
function get_userVar(): LongInt
vb
function get_userVar() As Integer
cs
int get_userVar()
java
int get_userVar()
py
def get_userVar()
php
function get_userVar()
es
function get_userVar()
cmd
YModule target get_userVar

On startup and after a device reboot, the value is always reset to zero.

Returns :

an integer corresponding to the value previously stored in this attribute

On failure, throws an exception or returns Y_USERVAR_INVALID.

module→hasFunction()module.hasFunction()module.hasFunction()module→hasFunction()[module hasFunction: ]module.hasFunction()module.hasFunction()module.hasFunction()module.hasFunction()module.hasFunction()module→hasFunction()module.hasFunction()YModule hasFunction

Tests if the device includes a specific function.

js
function hasFunction(funcId)
nodejs
function hasFunction(funcId)
cpp
bool hasFunction(string funcId)
m
-(bool) hasFunction: (NSString*) funcId
pas
function hasFunction(funcId: string): boolean
vb
function hasFunction() As Boolean
cs
bool hasFunction(string funcId)
java
boolean hasFunction(String funcId)
py
def hasFunction(funcId)
php
function hasFunction($funcId)
es
function hasFunction(funcId)
cmd
YModule target hasFunction funcId

This method takes a function identifier and returns a boolean.

Parameters :

funcIdthe requested function identifier

Returns :

true if the device has the function identifier

module→isOnline()module.isOnline()module.isOnline()module→isOnline()[module isOnline]module.isOnline()module.isOnline()module.isOnline()module.isOnline()module.isOnline()module→isOnline()module.isOnline()

Checks if the module is currently reachable, without raising any error.

js
function isOnline()
nodejs
function isOnline()
cpp
bool isOnline()
m
-(BOOL) isOnline
pas
function isOnline(): boolean
vb
function isOnline() As Boolean
cs
bool isOnline()
java
boolean isOnline()
py
def isOnline()
php
function isOnline()
es
function isOnline()

If there are valid cached values for the module, that have not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the requested module.

Returns :

true if the module can be reached, and false otherwise

module→isOnline_async()module.isOnline_async()module.isOnline_async()

Checks if the module is currently reachable, without raising any error.

js
function isOnline_async(callback, context)
nodejs
function isOnline_async(callback, context)

If there are valid cached values for the module, that have not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the requested module.

This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox Javascript VM that does not implement context switching during blocking I/O calls.

Parameters :

callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving module object and the boolean result
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

module→load()module.load()module.load()module→load()[module load: ]module.load()module.load()module.load()module.load()module.load()module→load()module.load()

Preloads the module cache with a specified validity duration.

js
function load(msValidity)
nodejs
function load(msValidity)
cpp
YRETCODE load(int msValidity)
m
-(YRETCODE) load: (int) msValidity
pas
function load(msValidity: integer): YRETCODE
vb
function load(ByVal msValidity As Integer) As YRETCODE
cs
YRETCODE load(ulong msValidity)
java
int load(long msValidity)
py
def load(msValidity)
php
function load($msValidity)
es
function load(msValidity)

By default, whenever accessing a device, all module attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network traffic for instance.

Parameters :

msValidityan integer corresponding to the validity attributed to the loaded module parameters, in milliseconds

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→load_async()module.load_async()module.load_async()

Preloads the module cache with a specified validity duration (asynchronous version).

js
function load_async(msValidity, callback, context)
nodejs
function load_async(msValidity, callback, context)

By default, whenever accessing a device, all module attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network traffic for instance.

This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox javascript VM that does not implement context switching during blocking I/O calls. See the documentation section on asynchronous Javascript calls for more details.

Parameters :

msValidityan integer corresponding to the validity of the loaded module parameters, in milliseconds
callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving module object and the error code (or YAPI_SUCCESS)
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

module→log()module.log()module.log()module→log()[module log: ]module.log()module.log()module.log()module.log()module.log()module→log()module.log()YModule log

Adds a text message to the device logs.

js
function log(text)
nodejs
function log(text)
cpp
int log(string text)
m
-(int) log: (NSString*) text
pas
function log(text: string): LongInt
vb
function log() As Integer
cs
int log(string text)
java
int log(String text)
py
def log(text)
php
function log($text)
es
function log(text)
cmd
YModule target log text

This function is useful in particular to trace the execution of HTTP callbacks. If a newline is desired after the message, it must be included in the string.

Parameters :

textthe string to append to the logs.

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→nextModule()module.nextModule()module.nextModule()module→nextModule()[module nextModule]module.nextModule()module.nextModule()module.nextModule()module.nextModule()module.nextModule()module→nextModule()module.nextModule()

Continues the module enumeration started using yFirstModule().

js
function nextModule()
nodejs
function nextModule()
cpp
YModule * nextModule()
m
-(YModule*) nextModule
pas
function nextModule(): TYModule
vb
function nextModule() As YModule
cs
YModule nextModule()
java
YModule nextModule()
py
def nextModule()
php
function nextModule()
es
function nextModule()

Returns :

a pointer to a YModule object, corresponding to the next module found, or a null pointer if there are no more modules to enumerate.

module→reboot()module.reboot()module.reboot()module→reboot()[module reboot: ]module.reboot()module.reboot()module.reboot()module.reboot()module.reboot()module→reboot()module.reboot()YModule reboot

Schedules a simple module reboot after the given number of seconds.

js
function reboot(secBeforeReboot)
nodejs
function reboot(secBeforeReboot)
cpp
int reboot(int secBeforeReboot)
m
-(int) reboot: (int) secBeforeReboot
pas
function reboot(secBeforeReboot: LongInt): LongInt
vb
function reboot() As Integer
cs
int reboot(int secBeforeReboot)
java
int reboot(int secBeforeReboot)
py
def reboot(secBeforeReboot)
php
function reboot($secBeforeReboot)
es
function reboot(secBeforeReboot)
cmd
YModule target reboot secBeforeReboot

Parameters :

secBeforeRebootnumber of seconds before rebooting

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→registerLogCallback()module→registerLogCallback()[module registerLogCallback: ]module.registerLogCallback()module.registerLogCallback()module.registerLogCallback()module.registerLogCallback()

Registers a device log callback function.

cpp
void registerLogCallback(YModuleLogCallback callback)
m
-(void) registerLogCallback: (YModuleLogCallback) callback
vb
function registerLogCallback(ByVal callback As YModuleLogCallback) As Integer
cs
int registerLogCallback(LogCallback callback)
java
void registerLogCallback(LogCallback callback)
py
def registerLogCallback(callback)

This callback will be called each time that a module sends a new log message. Mostly useful to debug a Yoctopuce module.

Parameters :

callbackthe callback function to call, or a null pointer. The callback function should take two arguments: the module object that emitted the log message, and the character string containing the log.

module→revertFromFlash()module.revertFromFlash()module.revertFromFlash()module→revertFromFlash()[module revertFromFlash]module.revertFromFlash()module.revertFromFlash()module.revertFromFlash()module.revertFromFlash()module.revertFromFlash()module→revertFromFlash()module.revertFromFlash()YModule revertFromFlash

Reloads the settings stored in the nonvolatile memory, as when the module is powered on.

js
function revertFromFlash()
nodejs
function revertFromFlash()
cpp
int revertFromFlash()
m
-(int) revertFromFlash
pas
function revertFromFlash(): LongInt
vb
function revertFromFlash() As Integer
cs
int revertFromFlash()
java
int revertFromFlash()
py
def revertFromFlash()
php
function revertFromFlash()
es
function revertFromFlash()
cmd
YModule target revertFromFlash

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→saveToFlash()module.saveToFlash()module.saveToFlash()module→saveToFlash()[module saveToFlash]module.saveToFlash()module.saveToFlash()module.saveToFlash()module.saveToFlash()module.saveToFlash()module→saveToFlash()module.saveToFlash()YModule saveToFlash

Saves current settings in the nonvolatile memory of the module.

js
function saveToFlash()
nodejs
function saveToFlash()
cpp
int saveToFlash()
m
-(int) saveToFlash
pas
function saveToFlash(): LongInt
vb
function saveToFlash() As Integer
cs
int saveToFlash()
java
int saveToFlash()
py
def saveToFlash()
php
function saveToFlash()
es
function saveToFlash()
cmd
YModule target saveToFlash

Warning: the number of allowed save operations during a module life is limited (about 100000 cycles). Do not call this function within a loop.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_allSettings()
module→setAllSettings()
module.set_allSettings()module.set_allSettings()module→set_allSettings()[module setAllSettings: ]module.set_allSettings()module.set_allSettings()module.set_allSettings()module.set_allSettings()module.set_allSettings()module→set_allSettings()module.set_allSettings()YModule set_allSettings

Restores all the settings of the device.

js
function set_allSettings(settings)
nodejs
function set_allSettings(settings)
cpp
int set_allSettings(string settings)
m
-(int) setAllSettings: (NSData*) settings
pas
function set_allSettings(settings: TByteArray): LongInt
vb
procedure set_allSettings()
cs
int set_allSettings()
java
int set_allSettings(byte[] settings)
py
def set_allSettings(settings)
php
function set_allSettings($settings)
es
function set_allSettings(settings)
cmd
YModule target set_allSettings settings

Useful to restore all the logical names and calibrations parameters of a module from a backup.Remember to call the saveToFlash() method of the module if the modifications must be kept.

Parameters :

settingsa binary buffer with all the settings.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_allSettingsAndFiles()
module→setAllSettingsAndFiles()
module.set_allSettingsAndFiles()module.set_allSettingsAndFiles()module→set_allSettingsAndFiles()[module setAllSettingsAndFiles: ]module.set_allSettingsAndFiles()module.set_allSettingsAndFiles()module.set_allSettingsAndFiles()module.set_allSettingsAndFiles()module.set_allSettingsAndFiles()module→set_allSettingsAndFiles()module.set_allSettingsAndFiles()YModule set_allSettingsAndFiles

Restores all the settings and uploaded files to the module.

js
function set_allSettingsAndFiles(settings)
nodejs
function set_allSettingsAndFiles(settings)
cpp
int set_allSettingsAndFiles(string settings)
m
-(int) setAllSettingsAndFiles: (NSData*) settings
pas
function set_allSettingsAndFiles(settings: TByteArray): LongInt
vb
procedure set_allSettingsAndFiles()
cs
int set_allSettingsAndFiles()
java
int set_allSettingsAndFiles(byte[] settings)
py
def set_allSettingsAndFiles(settings)
php
function set_allSettingsAndFiles($settings)
es
function set_allSettingsAndFiles(settings)
cmd
YModule target set_allSettingsAndFiles settings

This method is useful to restore all the logical names and calibrations parameters, uploaded files etc. of a device from a backup. Remember to call the saveToFlash() method of the module if the modifications must be kept.

Parameters :

settingsa binary buffer with all the settings.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_beacon()
module→setBeacon()
module.set_beacon()module.set_beacon()module→set_beacon()[module setBeacon: ]module.set_beacon()module.set_beacon()module.set_beacon()module.set_beacon()module.set_beacon()module→set_beacon()module.set_beacon()YModule set_beacon

Turns on or off the module localization beacon.

js
function set_beacon(newval)
nodejs
function set_beacon(newval)
cpp
int set_beacon(Y_BEACON_enum newval)
m
-(int) setBeacon: (Y_BEACON_enum) newval
pas
function set_beacon(newval: Integer): integer
vb
function set_beacon(ByVal newval As Integer) As Integer
cs
int set_beacon(int newval)
java
int set_beacon(int newval)
py
def set_beacon(newval)
php
function set_beacon($newval)
es
function set_beacon(newval)
cmd
YModule target set_beacon newval

Parameters :

newvaleither Y_BEACON_OFF or Y_BEACON_ON

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_logicalName()
module→setLogicalName()
module.set_logicalName()module.set_logicalName()module→set_logicalName()[module setLogicalName: ]module.set_logicalName()module.set_logicalName()module.set_logicalName()module.set_logicalName()module.set_logicalName()module→set_logicalName()module.set_logicalName()YModule set_logicalName

Changes the logical name of the module.

js
function set_logicalName(newval)
nodejs
function set_logicalName(newval)
cpp
int set_logicalName(const string& newval)
m
-(int) setLogicalName: (NSString*) newval
pas
function set_logicalName(newval: string): integer
vb
function set_logicalName(ByVal newval As String) As Integer
cs
int set_logicalName(string newval)
java
int set_logicalName(String newval)
py
def set_logicalName(newval)
php
function set_logicalName($newval)
es
function set_logicalName(newval)
cmd
YModule target set_logicalName newval

You can use yCheckLogicalName() prior to this call to make sure that your parameter is valid. Remember to call the saveToFlash() method of the module if the modification must be kept.

Parameters :

newvala string corresponding to the logical name of the module

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_luminosity()
module→setLuminosity()
module.set_luminosity()module.set_luminosity()module→set_luminosity()[module setLuminosity: ]module.set_luminosity()module.set_luminosity()module.set_luminosity()module.set_luminosity()module.set_luminosity()module→set_luminosity()module.set_luminosity()YModule set_luminosity

Changes the luminosity of the module informative leds.

js
function set_luminosity(newval)
nodejs
function set_luminosity(newval)
cpp
int set_luminosity(int newval)
m
-(int) setLuminosity: (int) newval
pas
function set_luminosity(newval: LongInt): integer
vb
function set_luminosity(ByVal newval As Integer) As Integer
cs
int set_luminosity(int newval)
java
int set_luminosity(int newval)
py
def set_luminosity(newval)
php
function set_luminosity($newval)
es
function set_luminosity(newval)
cmd
YModule target set_luminosity newval

The parameter is a value between 0 and 100. Remember to call the saveToFlash() method of the module if the modification must be kept.

Parameters :

newvalan integer corresponding to the luminosity of the module informative leds

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_userData()
module→setUserData()
module.set_userData()module.set_userData()module→set_userData()[module setUserData: ]module.set_userData()module.set_userData()module.set_userData()module.set_userData()module.set_userData()module→set_userData()module.set_userData()

Stores a user context provided as argument in the userData attribute of the function.

js
function set_userData(data)
nodejs
function set_userData(data)
cpp
void set_userData(void* data)
m
-(void) setUserData: (id) data
pas
procedure set_userData(data: Tobject)
vb
procedure set_userData(ByVal data As Object)
cs
void set_userData(object data)
java
void set_userData(Object data)
py
def set_userData(data)
php
function set_userData($data)
es
function set_userData(data)

This attribute is never touched by the API, and is at disposal of the caller to store a context.

Parameters :

dataany kind of object to be stored

module→set_userVar()
module→setUserVar()
module.set_userVar()module.set_userVar()module→set_userVar()[module setUserVar: ]module.set_userVar()module.set_userVar()module.set_userVar()module.set_userVar()module.set_userVar()module→set_userVar()module.set_userVar()YModule set_userVar

Returns the value previously stored in this attribute.

js
function set_userVar(newval)
nodejs
function set_userVar(newval)
cpp
int set_userVar(int newval)
m
-(int) setUserVar: (int) newval
pas
function set_userVar(newval: LongInt): integer
vb
function set_userVar(ByVal newval As Integer) As Integer
cs
int set_userVar(int newval)
java
int set_userVar(int newval)
py
def set_userVar(newval)
php
function set_userVar($newval)
es
function set_userVar(newval)
cmd
YModule target set_userVar newval

On startup and after a device reboot, the value is always reset to zero.

Parameters :

newvalan integer

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module→triggerFirmwareUpdate()[module triggerFirmwareUpdate: ]module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module→triggerFirmwareUpdate()module.triggerFirmwareUpdate()YModule triggerFirmwareUpdate

Schedules a module reboot into special firmware update mode.

js
function triggerFirmwareUpdate(secBeforeReboot)
nodejs
function triggerFirmwareUpdate(secBeforeReboot)
cpp
int triggerFirmwareUpdate(int secBeforeReboot)
m
-(int) triggerFirmwareUpdate: (int) secBeforeReboot
pas
function triggerFirmwareUpdate(secBeforeReboot: LongInt): LongInt
vb
function triggerFirmwareUpdate() As Integer
cs
int triggerFirmwareUpdate(int secBeforeReboot)
java
int triggerFirmwareUpdate(int secBeforeReboot)
py
def triggerFirmwareUpdate(secBeforeReboot)
php
function triggerFirmwareUpdate($secBeforeReboot)
es
function triggerFirmwareUpdate(secBeforeReboot)
cmd
YModule target triggerFirmwareUpdate secBeforeReboot

Parameters :

secBeforeRebootnumber of seconds before rebooting

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

module→updateFirmware()module.updateFirmware()module.updateFirmware()module→updateFirmware()[module updateFirmware: ]module.updateFirmware()module.updateFirmware()module.updateFirmware()module.updateFirmware()module.updateFirmware()module→updateFirmware()module.updateFirmware()YModule updateFirmware

Prepares a firmware update of the module.

js
function updateFirmware(path)
nodejs
function updateFirmware(path)
cpp
YFirmwareUpdate updateFirmware(string path)
m
-(YFirmwareUpdate*) updateFirmware: (NSString*) path
pas
function updateFirmware(path: string): TYFirmwareUpdate
vb
function updateFirmware() As YFirmwareUpdate
cs
YFirmwareUpdate updateFirmware(string path)
java
YFirmwareUpdate updateFirmware(String path)
py
def updateFirmware(path)
php
function updateFirmware($path)
es
function updateFirmware(path)
cmd
YModule target updateFirmware path

This method returns a YFirmwareUpdate object which handles the firmware update process.

Parameters :

paththe path of the .byn file to use.

Returns :

a YFirmwareUpdate object or NULL on error.

module→updateFirmwareEx()module.updateFirmwareEx()module.updateFirmwareEx()module→updateFirmwareEx()[module updateFirmwareEx: ]module.updateFirmwareEx()module.updateFirmwareEx()module.updateFirmwareEx()module.updateFirmwareEx()module.updateFirmwareEx()module→updateFirmwareEx()module.updateFirmwareEx()YModule updateFirmwareEx

Prepares a firmware update of the module.

js
function updateFirmwareEx(path, force)
nodejs
function updateFirmwareEx(path, force)
cpp
YFirmwareUpdate updateFirmwareEx(string path, bool force)
m
-(YFirmwareUpdate*) updateFirmwareEx: (NSString*) path
  : (bool) force
pas
function updateFirmwareEx(path: string, force: boolean): TYFirmwareUpdate
vb
function updateFirmwareEx() As YFirmwareUpdate
cs
YFirmwareUpdate updateFirmwareEx(string path, bool force)
java
YFirmwareUpdate updateFirmwareEx(String path, boolean force)
py
def updateFirmwareEx(path, force)
php
function updateFirmwareEx($path, $force)
es
function updateFirmwareEx(path, force)
cmd
YModule target updateFirmwareEx path force

This method returns a YFirmwareUpdate object which handles the firmware update process.

Parameters :

paththe path of the .byn file to use.
forcetrue to force the firmware update even if some prerequisites appear not to be met

Returns :

a YFirmwareUpdate object or NULL on error.

module→wait_async()module.wait_async()module.wait_async()module.wait_async()

Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.

js
function wait_async(callback, context)
nodejs
function wait_async(callback, context)
es
function wait_async(callback, context)

The callback function can therefore freely issue synchronous or asynchronous commands, without risking to block the Javascript VM.

Parameters :

callbackcallback function that is invoked when all pending commands on the module are completed. The callback function receives two arguments: the caller-specific context object and the receiving function object.
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing.

22.3. SerialPort function interface

The SerialPort function interface allows you to fully drive a Yoctopuce serial port, to send and receive data, and to configure communication parameters (baud rate, bit count, parity, flow control and protocol). Note that Yoctopuce serial ports are not exposed as virtual COM ports. They are meant to be used in the same way as all Yoctopuce devices.

In order to use the functions described here, you should include:

js
<script type='text/javascript' src='yocto_spiport.js'></script>
nodejs
var yoctolib = require('yoctolib');
var YSpiPort = yoctolib.YSpiPort;
cpp
#include "yocto_spiport.h"
m
#import "yocto_spiport.h"
pas
uses yocto_spiport;
vb
yocto_spiport.vb
cs
yocto_spiport.cs
java
import com.yoctopuce.YoctoAPI.YSpiPort;
py
from yocto_spiport import *
php
require_once('yocto_spiport.php');
es
import { YSpiPort } from 'yoctolib-es'
Global functions
yFindSpiPort(func)

Retrieves a SPI port for a given identifier.

yFindSpiPortInContext(yctx, func)

Retrieves a SPI port for a given identifier in a YAPI context.

yFirstSpiPort()

Starts the enumeration of SPI ports currently accessible.

yFirstSpiPortInContext(yctx)

Starts the enumeration of SPI ports currently accessible.

YSpiPort methods
spiport→clearCache()

Invalidates the cache.

spiport→describe()

Returns a short text that describes unambiguously the instance of the SPI port in the form TYPE(NAME)=SERIAL.FUNCTIONID.

spiport→get_advertisedValue()

Returns the current value of the SPI port (no more than 6 characters).

spiport→get_currentJob()

Returns the name of the job file currently in use.

spiport→get_errCount()

Returns the total number of communication errors detected since last reset.

spiport→get_errorMessage()

Returns the error message of the latest error with the SPI port.

spiport→get_errorType()

Returns the numerical error code of the latest error with the SPI port.

spiport→get_friendlyName()

Returns a global identifier of the SPI port in the format MODULE_NAME.FUNCTION_NAME.

spiport→get_functionDescriptor()

Returns a unique identifier of type YFUN_DESCR corresponding to the function.

spiport→get_functionId()

Returns the hardware identifier of the SPI port, without reference to the module.

spiport→get_hardwareId()

Returns the unique hardware identifier of the SPI port in the form SERIAL.FUNCTIONID.

spiport→get_lastMsg()

Returns the latest message fully received (for Line and Frame protocols).

spiport→get_logicalName()

Returns the logical name of the SPI port.

spiport→get_module()

Gets the YModule object for the device on which the function is located.

spiport→get_module_async(callback, context)

Gets the YModule object for the device on which the function is located (asynchronous version).

spiport→get_protocol()

Returns the type of protocol used over the serial line, as a string.

spiport→get_rxCount()

Returns the total number of bytes received since last reset.

spiport→get_rxMsgCount()

Returns the total number of messages received since last reset.

spiport→get_shitftSampling()

Returns true when SDI line phase is shifted with regards to SDO line.

spiport→get_spiMode()

Returns the serial port communication parameters, as a string such as "125000,0,msb".

spiport→get_ssPolarity()

Returns the SS line polarity.

spiport→get_startupJob()

Returns the job file to use when the device is powered on.

spiport→get_txCount()

Returns the total number of bytes transmitted since last reset.

spiport→get_txMsgCount()

Returns the total number of messages send since last reset.

spiport→get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

spiport→get_voltageLevel()

Returns the voltage level used on the serial line.

spiport→isOnline()

Checks if the SPI port is currently reachable, without raising any error.

spiport→isOnline_async(callback, context)

Checks if the SPI port is currently reachable, without raising any error (asynchronous version).

spiport→load(msValidity)

Preloads the SPI port cache with a specified validity duration.

spiport→load_async(msValidity, callback, context)

Preloads the SPI port cache with a specified validity duration (asynchronous version).

spiport→muteValueCallbacks()

Disable the propagation of every new advertised value to the parent hub.

spiport→nextSpiPort()

Continues the enumeration of SPI ports started using yFirstSpiPort().

spiport→queryLine(query, maxWait)

Sends a text line query to the serial port, and reads the reply, if any.

spiport→readArray(nChars)

Reads data from the receive buffer as a list of bytes, starting at current stream position.

spiport→readBin(nChars)

Reads data from the receive buffer as a binary buffer, starting at current stream position.

spiport→readByte()

Reads one byte from the receive buffer, starting at current stream position.

spiport→readHex(nBytes)

Reads data from the receive buffer as a hexadecimal string, starting at current stream position.

spiport→readLine()

Reads a single line (or message) from the receive buffer, starting at current stream position.

spiport→readMessages(pattern, maxWait)

Searches for incoming messages in the serial port receive buffer matching a given pattern, starting at current position.

spiport→readStr(nChars)

Reads data from the receive buffer as a string, starting at current stream position.

spiport→read_avail()

Returns the number of bytes available to read in the input buffer starting from the current absolute stream position pointer of the API object.

spiport→read_seek(absPos)

Changes the current internal stream position to the specified value.

spiport→read_tell()

Returns the current absolute stream position pointer of the API object.

spiport→registerValueCallback(callback)

Registers the callback function that is invoked on every change of advertised value.

spiport→reset()

Clears the serial port buffer and resets counters to zero.

spiport→selectJob(jobfile)

Load and start processing the specified job file.

spiport→set_SS(val)

Manually sets the state of the SS line.

spiport→set_currentJob(newval)

Changes the job to use when the device is powered on.

spiport→set_logicalName(newval)

Changes the logical name of the SPI port.

spiport→set_protocol(newval)

Changes the type of protocol used over the serial line.

spiport→set_shitftSampling(newval)

Changes the SDI line sampling shift.

spiport→set_spiMode(newval)

Change