notes for esp32c3 & embassy

[elasticdotventures]

Documentation

I'm trying to put together some signposting to link embassy-rs and ultimately drogue-device

Must

• [ x ] The code compiles without errors or warnings.
• [ x ] All examples work.
• [ x ] cargo fmt was run.
• [ x ] Your changes were added to the CHANGELOG.md in the proper section.
• [ x ] You updated existing examples or added examples (if applicable).
• [ x ] Added examples are checked in CI

Nice to have

• You add a description of your work to this PR.
• You added proper docs for your newly added features and code.

[bugadani]

Where did you get this from?

I'd suggest familiarizing yourself with the ESP32 lineup and their peripherals. I don't think any ARM-based ESP32 exists, the C3 certainly isn't ARM. The SysTimer peripheral, that this feature coopts as the timebase is a 52 bit timer peripheral present in most ESP32s (it's there at least in the S2, S3, C3, and maybe more).

[elasticdotventures]

@bugadani - see cunninghams law.

I'm attempting to sift through the code and understand it, write up documentation with my guesses and hopefully get them corrected either in github or matrix.

I assumed (incorrectly) the systick was put in to provide compatibility for embassy-rs which seems stm32 centric, that's just what I was able to find/infer from searching & asking chatgpt. the documentation in this area is sparse.

I was trying to say that systick might be a better choice than timg0 if multiple architectures are important - because apparently I must choose one, and only one timer with no explanation why one is better or different than the other.

[MabezDev]

Thanks for bringing this to our attention, and thanks for the PR!

I've gone ahead and opened #835 instead as this PR only addresses the esp32c3, and duplicates some information we already have in the documentation.