Reverse voltage protection with RPi and Pico

Development Boards Raspberry Pi
1

My Pico will get 5V at its VIN pin, but will also sometimes be connected via USB to my RPi (for programming), which will also supply voltage. I need to protect both voltage sources from getting reverse voltage. I can put a diode on the VIN pin to protect that voltage source. How do I protect the RPi? Is there already reverse voltage protection for the USB on either the Pico or the RPi? Or do I need to make a custom USB cable that has a diode in it? Or maybe a USB cable with the V+ wire cut?

Thanks.

2

So this is done by applying external power to VSYS. There’s a diode between VSYS and VBUS to protect the power source coming through the USB. I should put a diode on VSYS to protect my other power supply from the USB voltage. Simple.