Virtually plug and unplug your USB connections with the USBHub3+

2023 October 16

Turning ports on and off with Python

No need to physically unplug cables; follow along as we demonstrate the interactive process of enabling and disabling ports, ensuring smooth USB device management.

It shouldn't have to happen, but sometimes you need to plug and unplug a USB device. Maybe the device needs to power cycle, maybe you need to enable devices one-by-one so they enumerate correctly.  Rather than having to physically unplug cables, you could use the Brainstem API to have the USBHub3+ vitually disconnect and reconnect a port.

We'll be working interactively in a Python console so you can see the results line-by-line. For more Python examples to get started, see here

First, power on the hub and connect one of the host ports to your computer

All of the VBus LEDs on the front panel should be on. If you haven’t already, install the brainstem package (See the Quickstart Guide for more detail)

>>> !pip install brainstem --upgrade

Then import the brainstem library

>>> import brainstem

Create an instance of the USBHub3p called "hub"

>>> hub = brainstem.stem.USBHub3p()

Discover and connect to the hub

>>> hub.discoverAndConnect(

(A return value of 0 means no error)

Let's plug a Super Speed USB 3 device into port 0.  A green LED should turn on next to port 0. (The LED would be yellow for a High Speed device)

Now let's "unplug" by disabling port 0.

>>> hub.usb.setPortDisable(0)

The power and data LEDs for port 0 should both be off.  It's like we're unplugged!

Re-enable port 0:

>>> hub.usb.setPortEnable(0)


...and now we're plugged back in.

Let's check the port state.

>>> result=hub.usb.getPortState(0)
>>> format(result.value, 'b')

The result is bit-packed, see the full table.

1 0 1 1
USB3 Data Enabled Reserved USB2 Data Enabled USB Vbus Enabled

Vbus, USB2 data, and USB3 data are enabled.

The USBHub3+ lets you virtually manage USB connections without the need for manual plugging or unplugging. Through the Brainstem API and Python commands, users can easily enable or disable ports, simulating the process of physical connection. This capability is especially helpful when devices need a power cycle or need to be enabled in a sequence.

What else could you do with USBHub3+?


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