embedded-hal VS embassy

What is the difference between this and https://github.com/rust-embedded/embedded-hal/tree/master/embedded-hal-async?

Maybe worth mentioning if you (or someone else) hasn't seen it before, the embedded-wg is also working on an async version of the embedded-hal traits, embedded-hal-async.

In that case you want to keep most of the unsafe in the HAL crate, and expose an interface as safe as possible. To give you an idea, is it since 2018 that a "generic" DMA safe implementation is in discussion https://github.com/rust-embedded/embedded-hal/issues/37

Does something like embedded hal exist in the C/C++ world? ( https://github.com/rust-embedded/embedded-hal )

worth mentioning also is embedded-hal but my understanding is this has absolutely nothing to do with arduino, so despite being embedded probably not what I want.

The ecosystem is great and growing, It really benefits from a language-standard embedded HAL which makes writing cross-platform drivers a cinch - e.g., you can write a bit-banged MDIO driver and use it on anything that has a timer and a two IO pins, from a Zynq Ultrascale to an arduino. Sure, this is possible in C - but Rust really benefits from a less fragmented ecosystem here.

Have you thought about writing/contributing to embedded-hal compatible crates (a sensor module driver for example)? It's always good to contribute to an eco system.

📝 At the time of writing this post, it came to my attention that there is an additional HAL that targets STM32 device families (the stm32-hal). From what I figure, right now there seem to be two approaches for developing HALs. The first approach is trait driven so to speak where the embedded-hal is used as a foundation. The second approach is more application-driven and provides a high-level API that targets several families of a device. However, this exists only for the stm32 through the stm32-hal. Right now, the first approach is what I found to be more widespread as it covers different microcontrollers and what this post is based on.

I can write a library for an OLED device that is driven by an platform agnostic I2C device that will run on any microcontroller that implements the necessary abstractions.

The `embedded-hal` (https://github.com/rust-embedded/embedded-hal) are these abstractions that allow this to happen

Yes but there needs to be appropriate libraries available such as HAL. Well it doesn't have to but it makes my life as a beginner in both much easier. But its probably matter of time because i predict that this chip will be very popular in Rust embedded.

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...