Embedded Development

Domain Constraints

Critical Rules

• Cannot use heap (no allocator) — use heapless::Vec<T, N> and arrays for deterministic memory.
• Shared state must be interrupt-safe — ISR can preempt at any time. Use Mutex<RefCell<T>> + critical section.
• Peripherals must have clear ownership — HAL takes ownership via singletons to prevent conflicting access.

Layer Stack

Framework Comparison

Key Crates

Static Peripheral Pattern

#![no_std]
#![no_main]

use cortex_m::interrupt::{self, Mutex};
use core::cell::RefCell;

static LED: Mutex<RefCell<Option<Led>>> = Mutex::new(RefCell::new(None));

#[entry]
fn main() -> ! {
    let dp = pac::Peripherals::take().unwrap();
    let led = Led::new(dp.GPIOA);

    interrupt::free(|cs| {
        LED.borrow(cs).replace(Some(led));
    });

    loop {
        interrupt::free(|cs| {
            if let Some(led) = LED.borrow(cs).borrow_mut().as_mut() {
                led.toggle();
            }
        });
    }
}

Common Mistakes