embassy

name	embassy
description	Embassy async embedded framework for Rust. Use when working with async/await in no_std embedded contexts, task executors, or Embassy crates like embassy-executor, embassy-time, embassy-sync.
keywords	["embassy","async","await","no_std","embedded","executor","embassy-time","embassy-sync","embassy-executor","timer","channel","mutex","signal","spawner","interrupt"]

Embassy Async Embedded Framework

Embassy is a modern embedded framework using Rust's async/await for efficient, safe embedded programming.

Core Concepts

Async Executor

• No alloc, no heap: Tasks are statically allocated
• Single stack: No per-task stack sizing needed
• Compile-time transformation: Tasks become state machines
• No RTOS needed: Replaces kernel context switching

Low Power

• Executor automatically sleeps when idle
• Tasks wake via interrupts (no busy-loop polling)
• Ideal for battery-powered devices

Key Crates

embassy-executor

Async task runtime for embedded systems.

#![no_std]
#![no_main]

use embassy_executor::Spawner;

#[embassy_executor::main]
async fn main(spawner: Spawner) {
    spawner.spawn(background_task()).unwrap();
    // Main task continues...
}

#[embassy_executor::task]
async fn background_task() {
    loop {
        // Do work...
        Timer::after_secs(1).await;
    }
}

embassy-time

Timers, delays, and timeouts.

use embassy_time::{Timer, Duration, Instant};

// Delay
Timer::after(Duration::from_millis(100)).await;
Timer::after_secs(1).await;

// Timeout
let result = with_timeout(Duration::from_secs(5), async_operation()).await;

// Measuring time
let start = Instant::now();
do_work().await;
let elapsed = start.elapsed();

embassy-sync

Synchronization primitives for async contexts.

use embassy_sync::{
    mutex::Mutex,
    channel::Channel,
    signal::Signal,
};
use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;

// Shared state
static SHARED: Mutex<CriticalSectionRawMutex, u32> = Mutex::new(0);

// Channel for message passing
static CHANNEL: Channel<CriticalSectionRawMutex, Message, 4> = Channel::new();

// Signal for notifications
static SIGNAL: Signal<CriticalSectionRawMutex, ()> = Signal::new();

embassy-embedded-hal

Async traits for embedded-hal compatibility.

Additional Crates

Crate	Purpose
embassy-net	TCP, UDP, DHCP, ICMP networking
embassy-usb	Device-side USB (CDC, HID, custom)
embassy-boot	Power-fail-safe firmware updates
trouble	Bluetooth Low Energy 4.x/5.x

HAL Support

• embassy-stm32: All STM32 families
• embassy-nrf: Nordic nRF52, nRF53, nRF54, nRF91
• embassy-rp: Raspberry Pi RP2040, RP2350
• embassy-mspm0: Texas Instruments MSPM0
• esp-hal: Espressif ESP32 series
• ch32-hal: WCH RISC-V chips

Resources

• Embassy Website
• Embassy Book
• GitHub Repository
• API Documentation