svd2nim VS micronucleus

Nim's maintainer agrees with you I believe, and the API is as you suggest (volatileLoad and volatileStore): https://nim-lang.org/docs/volatile.html

However, under the hood, Nim compiles to C. So these are macros that typecast to volatile, does the read (or write), then casts back to non-volatile.

(Small plug for my nim project that is somewhat related to OP: https://github.com/EmbeddedNim/svd2nim)

C++ has decent industry acceptance in embedded nowadays, or at least that has been my impression.

After C++, rust is likely the most popular, quite a lot of effort has been put into running rust on embedded, see eg https://github.com/rust-embedded. However, once again to my understanding, industry acceptance is still highly marginal.

After that, there's a bunch of toy-ish efforts to run other languages. Zig, nim, python and javascript variants, etc. Usually anything that has C ABI compatibility should be possible to get up and running (without writing a compiler backend from scratch). I've had fun with some toy projects using nim for ARM cortex-M targets (https://github.com/EmbeddedNim/svd2nim, https://github.com/auxym/nim-on-samd21, https://github.com/EmbeddedNim/picostdlib).

Using Nim (and eg svd2nim to generate the equivalent of CMSIS headers for register access in pure nim), it would be entirely possible to write even the low level stuff (SPI drivers and whatnot) in 100% nim, with the same performance as C and better safety (better static type system and compile-time checks, etc). Runtime (eg overflow) checks and garbage collection are available (at the cost of some performance) but optional. See eg. a pretty basic higher-level API for GPIO access, that provides native performance, since the abstraction is implemented as macros (compile-time abstraction): https://github.com/auxym/nim-on-samd21/blob/master/src/port....

Any chance your MCU is ARM? If so check out my project to generate the register mappings from CMSIS SVD files: https://github.com/EmbeddedNim/svd2nim

To be clear: Ratel isn't my project, just something I'm following due to interest.

In the interest of shameless self promotion :), my own experimentations are :

https://github.com/EmbeddedNim/svd2nim

https://github.com/auxym/nim-on-samd21

And I've used and contributed to picostdlib (https://github.com/beef331/picostdlib), the rp2040 support library.

All just as a hobby, but it's interesting to learn that some companies are actually looking into Nim for firmware! Embedded seems like such a slow moving industry. I believe the author of Nesper and Nephyr also developed them for professional work.

Many vendors provide svd files which describe the hardware registers. It's possible to convert the svd automatically like they do for C. Here's an example for Nim [1]. Rust has one as well.

Though I agree that MCU's currently involve a lot of busy work. It's why I'm working on building a nice system building on Zephyr using Nim [2]. It's pretty great to write a few dozen lines of concise memory safe code to do somethinguseful, and then be able to run it on dozens different MCUs.

It'd be great if there was more Ada core in these systems, as Zephyr is all built in C. At least it's modern clean C and well tested.

1: https://github.com/EmbeddedNim/svd2nim

If you're curious, I have this in MVP status at the moment: https://github.com/auxym/svd2nim

You can actually bit-bang low speed USB on Arduino [0]. There is even a bootloader [1] for ATtiny. It is obviously not compatible with Arduino, but those tiny boards look too cute to ignore [2]. Also, you can use USB port both for downloading firmware and your application.

[0] https://github.com/obdev/v-usb

[1] https://github.com/micronucleus/micronucleus

[2] https://cpldcpu.wordpress.com/2014/04/25/the-nanite-85/

The Digispark[1] and its clones use the ATTINY85 and offer flashing over USB via the Micronucleus bootloader[2] using V-USB[3]. It comes at the cost of a significant chunk of flash storage, but the convenience is excellent. Plus, V-USB support means you can emulate all sorts of USB devices. I've used it to build a DIY NES controller adapter, but it's commonly used as a cheap Rubber Ducky[4]. For projects where USB interfacing makes sense, it can be a good fit.

1: http://digistump.com/products/1

2: https://github.com/micronucleus/micronucleus

3: https://www.obdev.at/products/vusb/index.html

4: https://shop.hak5.org/products/usb-rubber-ducky-deluxe

So it looks like they're using the micronucleus bootloader for the linked example. That bootloader not only does the normal bootloader job, but also acts as a bitbanging USB device in order to communicate with the computer over USB. The USB bitbanging is a huge endeavor to undertake on top of writing a bootloader.