Raspberry Pi Pico Multitasker

I am very interested in the RP2040, the chip Raspberry Pi designed themselves, as it seemed unique and packs a lot of power into a small space. Because of this, I thought it would be fun to use it as the base for my final project, since we had a lot of flexibility in what we could choose.

I created a library where the user can set up a couple of tasks and have the Pico execute them in parallel. You can’t run a proper operating system on these boards, so this requires interfacing with the processor directly. The mechanism is relatively simple: trigger an interrupt every few milliseconds, and in the interrupt handler, save the current context and switch to the next one. This took me out of my usual wheelhouse, as I had never dealt with anything this low-level before, and it meant writing a good chunk of ARM assembly to trigger the interrupts, save the context, and so on.

As this sort of thing requires a good debugging environment, I also set up my own Pico Probe, which was fun and interesting in itself.