Why Rust is Transforming Embedded Systems Development

After using C and C++ for embedded systems for over 6 years, I recently completed a major project in Rust at Cerulion. The experience was transformative. Here's why I believe Rust is the future of embedded systems development.

The Memory Safety Promise

In embedded systems, a memory bug isn't just a crash—it could be a safety hazard. Rust eliminates entire classes of bugs at compile time:

• Buffer overflows
• Use-after-free
• Data races
• Null pointer dereferences

Real Example: Zero-Copy IPC

At Cerulion, we built a zero-copy IPC system in Rust. In C++, managing shared memory lifetimes would require careful manual tracking. In Rust:

pub struct SharedBuffer<T> {
    data: Arc<UnsafeCell<T>>,
    _marker: PhantomData<*const ()>,
}

unsafe impl<T: Send> Send for SharedBuffer<T> {}
unsafe impl<T: Sync> Sync for SharedBuffer<T> {}

The compiler ensures we can't accidentally share the buffer unsafely. When we need to break the rules, unsafe blocks make it explicit and auditable.

Zero-Cost Abstractions

Rust's abstractions compile down to the same code you'd write by hand. Take iterators:

// High-level, readable code
let sum: u32 = sensor_readings
    .iter()
    .filter(|r| r.is_valid())
    .map(|r| r.value)
    .sum();

// Compiles to the same assembly as:
let mut sum = 0u32;
for reading in sensor_readings {
    if reading.is_valid() {
        sum += reading.value;
    }
}

On embedded targets where every cycle counts, this is crucial.

The Embedded Rust Ecosystem

The ecosystem has matured significantly:

• embedded-hal: Hardware abstraction layer traits
• RTIC: Real-time interrupt-driven concurrency framework
• defmt: Efficient logging for constrained devices
• probe-rs: Debug probe support

Example: GPIO with embedded-hal

use embedded_hal::digital::v2::OutputPin;

fn blink<P: OutputPin>(led: &mut P, delay: &mut impl DelayMs<u32>) {
    led.set_high().ok();
    delay.delay_ms(500);
    led.set_low().ok();
    delay.delay_ms(500);
}

This code works on any microcontroller with an embedded-hal implementation.

Challenges and Trade-offs

Rust isn't perfect for embedded. The challenges:

1. Learning curve: Ownership and lifetimes take time to master
2. Ecosystem gaps: Some peripherals lack drivers
3. Binary size: Needs careful configuration for tiny targets
4. Team adoption: Finding Rust-skilled embedded developers is harder

My Recommendation

For new safety-critical projects, seriously consider Rust. The upfront investment in learning pays dividends in:

• Fewer runtime bugs
• More confident refactoring
• Better concurrency handling
• Clearer code intent

For existing C/C++ codebases, consider Rust for new modules or safety-critical components. The FFI is excellent.

Conclusion

Rust is transforming how we think about systems programming. In embedded systems, where bugs can have physical consequences, Rust's guarantees are invaluable. The future of safe, reliable embedded systems is being written in Rust.