embassy VS nrf-hal

thanks. looked that up. for the curious: https://embassy.dev/

Running the Embassy RP2040 USB CDC ACM serial example takes about 5 seconds on a Pico.

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

Async solves different problems, you can, for instance, have just a single-threaded CPU and still have a nice API if you have async-await. It might not be so cool at a higher level as Go's approach of channels and threads, but it's cool in embedded, read this:

https://github.com/embassy-rs/embassy?tab=readme-ov-file#rus...

"Rust's async/await allows for unprecedently easy and efficient multitasking in embedded systems. Tasks get transformed at compile time into state machines that get run cooperatively. It requires no dynamic memory allocation, and runs on a single stack, so no per-task stack size tuning is required. It obsoletes the need for a traditional RTOS with kernel context switching, and is faster and smaller than one!"

I'm just toying with Raspberry Pi Pico and it's pretty nice.

Go and Rust have different use cases, the async-await is nice at a low level.

I have not yet dipped by toes in the Rust waters, but reading about the embassy project is actually what piqued my curiosity about using C++ coroutines in embedded. Are you familiar with the project or have you found it lacking?

I think I get the basics (shoutout to the Rust Embedded Working Group!), and I've started looking for the stack I'd be using. I think Embassy is really amazing, as well as the work of the ESP team -- hats off.

> }

And this is how to do it using embassy, which is an async framework for embedded in rust:

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

> not good for embedded

embassy begs to differ

https://embassy.dev/

async/await is really just a syntax for building state machines in a way that resembles regular code. It's compiled down to the same code that you would write by hand anyway (early on it had some bloat in state size but I think it's all fixed now).

And embedded has a lot of state machines!

You can run multiple executors at different interrupt priority levels (with multiple tasks per executor), which allows tasks on the higher priority executor to interrupt other tasks. Here's an example https://github.com/embassy-rs/embassy/blob/main/examples/nrf...

You should try again. I think that code is verbose because of the borrowing and because you're trying to do a one-liner. I use the nrf-hal library with the nrf52840, and the code reads pretty nicely. Here's an example:

https://github.com/nrf-rs/nrf-hal/blob/master/examples/blink...

Reading nrf-hal source, unfortunately new does re-configure the UARTE, and there is not a new_unchecked. The solution I can think of is to duplicate the write code with nrf52833_hal::pac::UARTE0. The Uarte type does not contain any metadata, it exists purely to guard the init of UARTE.

Really good. Check out the examples in the nrf-hal repo. Also, if you don't mind forking out for some extra components the Knurling sessions by Ferrous Systems are ace.

The embedded HAL crates do this with extensive use of macros, for example: https://github.com/nrf-rs/nrf-hal/blob/aae17943efc24baffe30b...

This solution makes sense given the constraints of Rust, but there's quite a cost in terms of compiler time and cognitive overhead to understand what is going on.

(Aside: I didn't use the HAL in my Rust firmware, that's a higher layer of abstraction; I only used the PAC crates.)