USB-Mux is an Open-Source and Open-Hardware 2x2 USB 2.0 multiplexer.
It supports a single connection between one of the inputs to one of the outputs. Additionally, it can disconnect the outputs completely. Power flows from the selected input to the selected output. Inactive output ports are powerless.
Possible applications are switching USB connections in automated tests or power-cycle a hanging USB device via software.
Binary production files can be downloaded from the Releases page.
The multiplexer is controlled over USB via a virtual terminal. The virtual terminal will prompt "Mux:" and accepts a single number between 0 and 4 followed by a newline to select the multiplexer position. The meaning of the different numbers is printed on the PCB.
To connect to the virtual terminal on Linux you can use the following command:
picocom /dev/ttyACM0
Configure the firmware build environment in the 'src' directory with meson
and the supplied cross compiler file.
meson . build --cross-file cross.build
Then go into the 'build' directory and build it with ninja.
Now, you can program the CPU on the USB-Mux PCB with OpenOCD and an ST-Nucleo
board as programmer with ninja flash.
USB-Mux KiCAD hardware design files in the "hw" directory are licenses under the CERN-OHL-S v2, or (at your option) any later version.
The USB-Mux firmware in the "src" directory is licensed under the GNU GPLv3, or (at your option) any later version.