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Note: do not back-drive the 5V from an external power supply on the Rev00 board.
Arduino example code:
The processor is a Raspberry Pi RP2040. In the Arduino IDE, there are several compatible boards, but I've had the most success thinking of this as an Adafruit Feather RP2040
using the Arduino Philhower core. Here are instructions for setting up the Arduino IDE with that core.
https://learn.adafruit.com/adafruit-feather-rp2040-pico/arduino-ide-setup
These examples can be run on a bare PBJBread, but it might be more convenient to mount it onto a small breadboard, like this:
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