Ring oscillator with RP2040 PIO

This is a demonstration of the RP2040's PIO system, which let you run several state machines independently of the CPU. There's exactly 0 overhead and the state machines run a custom assembly language with simplified instructions.

In this example implementation of a ring oscillator, pin 1 is configured as a PIO input, and pin 2 as an output. Reading, inverting and writing is as simple as:

mov pins, !pins

Where pins is a meta keyword, with a different meaning in the first and second operand (output VS input, respectively).

Results

C implementation

The original C implementation can be found here.

MicroPython implementation

A MicroPython version with the same performance can be found here.