embedded-rust

嵌入式 Rust

用途

指导 Agent 进行嵌入式 Rust 开发：使用 probe-rs/cargo-embed 烧录和调试、使用 defmt 进行结构化日志记录、使用 RTIC 并发框架、使用 cortex-m-rt 启动、配置 no_std，以及选择 panic 处理程序。

触发条件

• “如何将我的 Rust 固件烧录到 MCU？”
• “如何调试我的嵌入式 Rust 程序？”
• “如何在嵌入式 Rust 中使用 defmt 进行日志记录？”
• “如何使用 RTIC 实现中断驱动的并发？”
• “对于嵌入式 Rust，#![no_std] #![no_main] 是什么意思？”
• “如何处理 no_std 嵌入式 Rust 中的 panic？”

工作流

1. 项目设置

# Cargo.toml
[package]
name = "my-firmware"
version = "0.1.0"
edition = "2021"

[dependencies]
cortex-m = { version = "0.7", features = ["critical-section-single-core"] }
cortex-m-rt = "0.7"
defmt = "0.3"
defmt-rtt = "0.4"
panic-probe = { version = "0.3", features = ["print-defmt"] }

# Embassy (async embedded) — alternative to RTIC
# embassy-executor = { version = "0.5", features = ["arch-cortex-m"] }

[profile.release]
opt-level = "s"       # size optimization for embedded
lto = true
codegen-units = 1
debug = true          # keep debug info for defmt/probe-rs

# .cargo/config.toml
[build]
target = "thumbv7em-none-eabihf"    # Cortex-M4F / M7

[target.thumbv7em-none-eabihf]
runner = "probe-rs run --chip STM32F411CEUx"    # auto-run after build
rustflags = ["-C", "link-arg=-Tlink.x"]         # cortex-m-rt linker script

2. 最小裸机程序

// src/main.rs
#![no_std]
#![no_main]

use cortex_m_rt::entry;
use defmt::info;
use defmt_rtt as _;      // RTT transport for defmt
use panic_probe as _;    // panic handler that prints via defmt

#[entry]
fn main() -> ! {
    info!("Booting up!");

    // Access peripherals via PAC or HAL
    let _core = cortex_m::Peripherals::take().unwrap();
    // let dp = stm32f4xx_hal::pac::Peripherals::take().unwrap();

    loop {
        info!("Running...");
        cortex_m::asm::delay(8_000_000);  // rough delay
    }
}

常见 MCU 的目标三元组：

MCU 系列	目标三元组
Cortex-M0/M0+	thumbv6m-none-eabi
Cortex-M3	thumbv7m-none-eabi
Cortex-M4（无 FPU）	thumbv7em-none-eabi
Cortex-M4F / M7	thumbv7em-none-eabihf
Cortex-M33	thumbv8m.main-none-eabihf
RISC-V RV32IMAC	riscv32imac-unknown-none-elf

rustup target add thumbv7em-none-eabihf

3. probe-rs — 烧录和调试

# Install probe-rs
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/probe-rs/probe-rs/releases/latest/download/probe-rs-tools-installer.sh | sh

# Flash firmware
probe-rs run --chip STM32F411CEUx target/thumbv7em-none-eabihf/release/firmware

# Interactive debug session
probe-rs debug --chip STM32F411CEUx target/thumbv7em-none-eabihf/release/firmware

# List connected probes
probe-rs list

# Supported chips
probe-rs chip list | grep STM32

使用 cargo：

# Using the runner in .cargo/config.toml
cargo run --release           # builds, flashes, and streams defmt logs
cargo build --release         # build only

4. defmt — 高效日志记录

defmt（反格式化器）会将日志字符串编码为整数，传输最少字节，并在主机端解码：

use defmt::{info, warn, error, debug, trace, Format};

// Basic logging
info!("Temperature: {} °C", temp);
warn!("Stack usage: {}/{}",  used, total);
error!("I2C error: {:?}", err);

// Derive Format for custom types
#[derive(Format)]
struct Packet { id: u8, len: u16 }

info!("Received: {:?}", pkt);

// Assertions (panic with defmt message)
defmt::assert_eq!(result, expected);
defmt::assert!(condition, "message with {}", value);

defmt 后端（选择一个）：

# RTT (fastest, needs debug probe connected)
defmt-rtt = "0.4"

# Semihosting (slower, works without RTT support)
defmt-semihosting = "0.1"

5. RTIC — 实时中断驱动并发

// Cargo.toml
// rtic = { version = "2", features = ["thumbv7-backend"] }

#[rtic::app(device = stm32f4xx_hal::pac, peripherals = true, dispatchers = [SPI1])]
mod app {
    use stm32f4xx_hal::{pac, prelude::*};
    use defmt::info;

    #[shared]
    struct Shared {
        counter: u32,
    }

    #[local]
    struct Local {}

    #[init]
    fn init(cx: init::Context) -> (Shared, Local) {
        info!("RTIC init");
        periodic_task::spawn().unwrap();
        (Shared { counter: 0 }, Local {})
    }

    #[task(shared = [counter])]
    async fn periodic_task(mut cx: periodic_task::Context) {
        loop {
            cx.shared.counter.lock(|c| *c += 1);
            info!("Count: {}", cx.shared.counter.lock(|c| *c));
            rtic_monotonics::systick::Systick::delay(500.millis()).await;
        }
    }

    #[task(binds = EXTI0, local = [], priority = 2)]
    fn button_isr(cx: button_isr::Context) {
        info!("Button pressed!");
    }
}

6. Panic 处理程序

Crate	行为	适用场景
panic-halt	无限循环	生产环境，无调试探针
panic-probe	defmt 消息 + 停止	使用 probe-rs 进行开发
panic-semihosting	GDB 半主机输出	使用 GDB 进行开发
panic-reset	硬复位	看门狗式恢复

# Choose exactly one panic handler
[dependencies]
panic-halt = "0.2"           # or:
panic-probe = { version = "0.3", features = ["print-defmt"] }

嵌入式 Rust 目标三元组参考，请参阅 references/embedded-rust-targets.md。

相关技能

• 使用 skills/embedded/openocd-jtag，了解基于 OpenOCD、可替代 probe-rs 的调试方式
• 使用 skills/rust/rust-no-std，了解 #![no_std] 的模式和限制
• 使用 skills/embedded/linker-scripts 配置内存布局
• 使用 skills/rust/rust-cross 设置交叉编译工具链