The YoctoHub-Shield is a 50x58mm electronic module enabling you to
add 4 ports to a YoctoHub-Ethernet or to a YoctoHub-Wireless. You can cascade several
of these YoctoHub-Shields on the same hub. As all Yoctopuce products, the YoctoHub-Shield is
plug-and-play: you only need to connect it to a hub for its ports to start working
immediately. No configuration is required.
The YoctoHub-Shield is not a USB hub. While using micro-USB type connectors,
its down ports use a proprietary protocol, simpler than USB. Therefore,
you cannot drive, or even power, USB devices other than Yoctopuce modules.
Yoctopuce thanks you for buying this YoctoHub-Shield and sincerely hopes that you
will be satisfied with it. The Yoctopuce engineers have put a large amount of
effort to ensure that your YoctoHub-Shield is easy to install anywhere and easy to
drive in all circumstances. If you are nevertheless disappointed
with this module, do not hesitate to contact Yoctopuce
|Trunk bus connectors
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.
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 .
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 support.
Trunk bus connector
The trunk bus connector is used to connect the YoctoHub-Shield to
the master hub and to chain shields. It is based on
10 pole Picoflex connectors.
This connector enables you to access the YoctoHub-Shield directly by USB with
the appropriate cable. It behaves exactly like any other Yoctopuce module.
Because using the YoctoHub-Shield is totally transparent, you most likely will
never need to use this debugging port.
You can connect up to four Yoctopuce modules on these ports.
They are then available as if they were connected directly to
the master YoctoHub. Beware, the protocol used between the YoctoHub-Shield
and the Yoctopuce modules is not USB, but a lighter proprietary protocol.
Therefore, the YoctoHub-Shield cannot manage devices other than Yoctopuce
modules. In particular, you cannot add ports to a YoctoHub-Shield by using
a standard USB hub.
Warning: the YoctoHub-Shield USB connectors are 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, using flux to avoid
bridges. Alternatively, you can solder a USB cable directly in the 1.27mm-spaced
holes near the connector.
The YoctoHub-Shield is designed to be connected to a master YoctoHub with the provided cable.
It is a simple ribbon cable with a 10 pole Picoflex connector at each end.
A YoctoHub-Shield connected to a YoctoHub
The cable provided with the YoctoHub-Shield is very short on purpose.
The bus linking all the shields with the master YoctoHub must be as
short as possible in order to maintain high quality communications.
We recommend that you keep the distance between the
master YoctoHub and the most remote YoctoHub-Shield under 75cm.
Keep this in mind if you decide to move the YoctoHub-Shield away using
your own cables.
Theoretically, you can chain up to 10 YoctoHub-Shields, which makes a total of
43 Yoctopuce modules connected to the same hub. However, the
total current a YoctoHub can provide being limited to 2A. Therefore, depending what
devices you use, that limit might be reached before you have connected 43 modules.
Moreover, the more connected modules you have, the more the whole risks to slow
down because of saturation of the bus (especially if you use modules that
share a lot of data). Note that you can control each port independently.
You can thus optimize power consumption and bandwidth by shutting off
the modules that you do not need.
You can chain several YoctoHub-Shields.
You do not need to put the YoctoHub at the end of the chain. Note, however,
that the YoctoHub-Wireless has a small design flaw: a tiny capacitor prevents you
from pushing down completely the Picoflex connector on one of the headers.
Use the other header or take a cutter to notch the ribbon cable connector.
Since the YoctoHub-Shield allows to build huge stacks of devices, it's tempting
to have several projects running at the same time on the same shield stack.
However, a Yoctopuce hub is able to manage only 8 connections in parallel. An
application using the Yoctopuce API to access a hub needs 2 connections, the
first one for the set/get functions, and the second one to manage callbacks and
plug-and-play events. Therefore, you can have up to 4 applications
talking to a hub at the same time. Trying with more will cause a many
connection errors. The VirtualHub counts as one application.
All the double-width Yoctopuce modules have assembly holes at
the same location. You can thus stack several YoctoHub-Shields,
which enables you to build very compact hubs with a large
number of ports. Make sure nevertheless that the complete device
is properly ventilated.
You can stack several YoctoHub-Shields
The YoctoHub-Shield is also designed to enable you to directly fix
on it four single-width modules, two on each side.
Make sure to assemble the modules on the correct side:
assembly holes and square pads must be aligned. If you assemble
the modules on the wrong side, polarities are inverted and you
risk to damage your equipment.
You can assemble up to four modules directly on a YoctoHub-Shield
You can find below a summary of the main technical characteristics
of your YoctoHub-Shield module.
|Protection class, according to IEC 61140
|Normal operating temperature
|Extended operating temperature‡
|RoHS III (2011/65/UE+2015/863)
|USB Vendor ID
|USB Device ID
|Harmonized tariff code