This repo contains a simple blinky-led example in embedded rust for the Adafruit Feather RP2040. The template includes code that will configure the USB peripheral as a serial port to allow for printing of formatted strings via the write! macro. Additionally, panic messages are sent to the serial port, and will show up when properly connected to a utility such as minicom, nRF terminal, or putty.
Most of this code is adapted from this repository -- thanks!