Unable to create Timer interrupt for stm32f4 about embassy HOT 1 OPEN

I'm not entirely sure what you're asking or if my answer is relevant to you, but the way to create a timer is this:

use embassy_time::{Timer, Duration};

Timer::after(Duration::from_millis(20)).await

You can then combine the timer with other things such as the read:

use embassy_futures::select::{select, Either};

match select(Timer::after(Duration::from_millis(20)), rx.read_until_idle(&mut buf)).await {
    Either::First(_) => {} // Timer fired!
    Either::Second(_) => {} // Data was read
}

It's not entirely clear to me why you'd want to do this, because read_until_idle kinda does what you describe internally, waiting until the RX is idle before returning.

from embassy.