Minimal System Reference Topologies

[SterlingPeet]

I recently decided to see if I could reasonably shoehorn the F Prime Zephyr Reference onto an ESP32, as an experiment in the grander scheme of attempting to find a home for the interesting platforms currently targeted in the F Prime Arduino.

This is effectively exploratory work to determine if we can drop the Arduino OSAL in favor of a proper RTOS for everything except the ATmega128 and ATmega2560. Those platforms require an external RAM add-on, so using Arduino was really a shim to avoid writing the peripheral support up front while requiring hardware that didn't neatly run out-of-the-box on official Arduino boards.

The fundamental problem the has pushed F Prime Arduino support into crisis comes from the toolchain management side of things. Arduino's IDE restructure and the advent of arduino-cli made it possible to choose your own IDE and do headless builds, but there is a lot of friction to maintaining a messy build adapter that serves primarily to appear accessible to the crowd familiar with the Arduino brand.

Reviving the F Prime Arduino OSAL is a different discussion topic, and if people want to debate its value, I can start a different discussion thread for that.

Back to the task at hand! Cramming Zephyr RTOS onto the ESP32 along with the full system reference topology is a lot of memory for that platform, and while I have managed to get downlink over UART working, commanding is still elusive. A preview of this work can be viewed here:

https://github.com/SterlingPeet/fprime-zephyr-reference/tree/esp32_preview

Terminal Screen Capture

So the big question is this: Is there (or should we have) a standard minimal system reference for very very small platforms, that gets a minimal no-frills deployment running?

No sequencing, no multi-step framing and deframing, maybe a single gpio blinker component supporting a command or two. Literally the minimum table stakes. Perhaps a platform viability test that [hopefully] doesn't require a developer to spend 3 days adjusting F Prime and editing topologies to find out if it will fit on the platform. Twelve active components feels a little to big for this scenario.

Thoughts?