doc: document usage

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King Kévin 2022-06-16 17:51:05 +02:00
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@ -49,7 +49,7 @@ the board uses proper impedance and differential signal routing to provide clean
design choice design choice
============= =============
USB 3.0 USB 2.0
------- -------
this hub is only for USB 2.0 devices. this hub is only for USB 2.0 devices.
@ -99,3 +99,29 @@ instead the following color scheme is used:
usage usage
===== =====
it mainly works like a regular USB hub, at least when it comes to the data transfer.
just plug the device in a port.
power on the Downstream Facing Ports (DFPs) is only available when the Upstream Facing Port (UFP) is connected.
the hub can operate as bus powered (power coming from the UFP), but it would not be able to provide more than 500 mA across all DFPs.
it is preferable to connect an external 5V power supply to be able to provide 500 mA on all DFPs.
this will also turn the hub into self powered, not using any power from the UFP.
alternatively, you can connect a 6 to 40V power supply on the other power input.
the power for the hub and the 5V for the DFP will be derivate from this higher voltage supply.
the same higher voltage will be available on the power output next to the individual DFPs.
a switch next to each DFP allows to turn off the power output on the USB and power ports.
the green LED is on when power output is available.
the power output on the USB and power ports can also be turned on/off remotely using standard USB commands.
this power output control is implemented in [uhubctl](https://github.com/mvp/uhubctl):
~~~
# list controllable USB hub ports
sudo uhubctl
# switch of port
uhubctl --action off --location 1-1.4 --ports 5
~~~
when too much current is drawn on the USB port, the error is reported to the host and the power output is automatically disabled.