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0 pointsthe__alchemist8d ago0 comments

Good article! I will give you my 2c, as someone in this space mostly for hobbies, but with one active work project:

Rust is fantastic for embedded. There are no hard obstacles. The reason to do it IMO is not memory safety, but because holistically the language and tools are (to me) nicer. Enums, namespacing, no headers, `cargo run --release` "just works". (I have found, at least in OSS, compiling C embedded project is a mess. Linker errors, you need to have a certain OS with certain dependencies, there are many scripts etc). Good error messages, easy to structure your programs in a reliable way etc. Overall, I just find it to be a better designed language.

I have found the most fundamental tooling for rust on Espressif's RiscV, and Cortex-M ARM for various STM-32 variants to be great. The cortex-m crate, defmt, and probe-rs, and the PAC project is fantastic.

On the down side, I have have to build my own tooling. I wrote and maintain my own HAL for STM32, and have had to write my own libraries for every piece of hardware. This comes with the territory of a new language, and suspect this will gradually improve this time - especially with vendor support. Because the fundamental libraries are around, this is just reading datasheets and making rust functions/structs etc that do the MMIO as described in the datasheets. Can be tedious (Especially if building a complete library instead of implementing what you need for a given project), but is not an obstacle.

My most complicated rust embedded firmware was a FPV-style UAS. I did it without an RTOS, using interrupt-based control flow.

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acstapleton8d ago

As a professional in the space, this echoes my experiences. I’m far more productive in Rust than C, despite having many more years programming embedded software in C. Cargo and the crate ecosystem are a dream compared to the lack of any easy-to-use build tooling and the difficulty of integrating third party libraries in C.

Furthermore, the code I’ve produced in Rust is generally as fast (or faster) than the code I’ve written in C for the same task, and it’s easier and faster to write.

And I also maintain an open source HAL for an STM32 family! Previously those have just been in house HALs in C because there were no such community efforts.

the__alchemistOP8d ago

Very cool! Which one? I have been using mostly G4 and H7 on my personal and work projects, but the HAL (`stm32-hal2` is the crate name) works for most of the one s in a certain time band; i.e. not any that were obsolte when I started it, and spotty or no support on some of the newer ones like U series and H5. And weaker / non-vetted support on MCU variants I haven't used, or haven't used a MCU/feature combo on.

I think in the future if I do an embedded rust project on a new MCU where there isn't an existing HAL, or one that is more work to repair than start over, I would just implement the subset needed for a project's reqs. Easier to keep track of scope that way. Currently the challenge is "X periph on Y variant of Z STM-32 family doesn't work under A condition" or "Doesn't work after this PAC update changed the syntax".

acstapleton7d ago

I’ve been developing https://github.com/stm32-rs/stm32h5xx-hal. It’s been a slow process adding functionality because I’ve focused on what we need from it, so it’s missing a lot of functionality. Making progress bit by bit though.

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