What is it?

The GPIO USB interruptor board plugs inline with a USB cable. It passes 5V power and D+/D- signals to your device under test. When you press the button, the D+/D- signals are momentarily disconnected.

Alternatively, a pin is broken out to connect to a microcontroller so the D+/D- can be disconnected programatically.

Why did you make it?

I work with USB devices as my day job. Re-plugging a USB cable gets really annoying. I know it is for most people as well.

This project is a similar concept to Paul Stoffregen's USB interruptor.

How to use it

The micro USB connector is the input and the USB A connector is the output. Press the button to momentarily interrupt the D+/D- signals. It's pretty simple to use! Your device under test will be re-enumerated by the host.

The GPIO USB interruptor can theoretically handle up to 1.5A of current -- I haven't tried it, but the USB connectors are rated for 1.5A and the PCB tracks are beefed up if you like to live dangerously.

Use shorter USB cables to minimize voltage drop if your device under test is sensitive to such things.

If you have a micro controller or FTDI UART in bit-bang mode that shares the same GND as your USB device, then you can use it to programmatically switch the GPIO USB interruptor. The break out pin is 3.3V active high. Pulling this pin low will disconnect the D+/D- signal lines until your controller pulls it back high. This pin is not 5V tolerant.

I personally use this connected to my FTDI UART's RST pin and use picocom to toggle the interruptor.