[scoutt]

I think the nature of microcontroller programming is already asynchronous. I mean, it's not that the only alternative to "async Rust" is an RTOS; a classic loop program with interrupts is already asynchronous. The only difference is you have to decide how you want to waste time waiting for events, and the same "energy saving" effect can also be achieved with a simple state machine and __WFI(), resulting in cleaner code with no dependencies whatsoever.

Also, it seems to me that Embassy takes over interrupt handlers? If that's the case, what if I want to deal with interrupts in a different way? Or what happens with interrupts that deal with many pins, like EXTI9_5_IRQHandler(), as if I want to use pin 9 with Async Rust, but the rest as a regular interrupt?

And Pin type is a poor name choice for embedded.

Also:

    ExtiInputFuture::new(self.pin.pin.pin.pin(), self.pin.pin.pin.port(), true, false).await

[rcxdude]

Yeah, you can always write async code by hand. It's a pain because you have to manually yield (as in, save your context, return to the main loop, and poll for the event to complete yourself) every time you wait for IO or a timer. For simple enough systems it's managable, in larger ones it quickly becomes a pain.