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STM32F303RE Embassy Blink Driver

Embedded Rust w/ Embassy blink driver.

Required Hardware

• STM32 Nucleo-F303RE Development Board

  • Development board based on the STM32F303RET6 microcontroller (ARM Cortex-M4F @ 72MHz).
  • Features: Onboard ST-LINK/V2-1 debugger, Arduino Uno V3 connectivity, 512KB Flash, 64KB RAM.
  • Ideal for embedded Rust development, async/await experimentation, and Embassy ecosystem learning.

• USB Mini-B Cable

  • For powering the board and programming via ST-LINK.

🚀 Quick Start

# Connect your STM32 Nucleo board via USB
# Run the installation script to set up dependencies
./install.sh

# Build and flash
cargo run --release

That's it! The firmware will build and flash automatically.

What's Included

• GPIO Control: Async LED blink on PA5 (green LED LD2)
• UART Output: Status messages via USART2 (ST-Link VCP at 115200 baud)
• Embassy Async Runtime: Clean async/await implementation for STM32F303RE

Hardware Pin Mapping

• LED (LD2): PA5 (GPIO output)
• UART TX: PA2 (USART2, connected to ST-Link VCP)
• User Button: PC13 (not used in this example)

Building

This project uses Embassy from crates.io with STM32F303RE support.

# Install the ARM Cortex-M4F target (already done if you followed setup)
rustup target add thumbv7em-none-eabihf

# Build
cargo build --release

Flashing to STM32F303RE

Method 1: probe-run (Recommended)

The easiest method using the integrated ST-LINK debugger:

# Install probe-run if not already installed
cargo install probe-run

# Build and flash
cargo run --release

The .cargo/config.toml is configured to use probe-run as the runner.

Method 2: probe-rs debug

For interactive debugging:

# Install probe-rs
cargo install probe-rs-tools --locked

# Build
cargo build --target thumbv7em-none-eabihf

# Start debug session
probe-rs debug --chip STM32F303RE --exe target/thumbv7em-none-eabihf/debug/stm32f303re-blink

Method 3: VS Code Debug (OpenOCD)

If you have VS Code with the Cortex-Debug extension:

# Install OpenOCD
brew install openocd

# Install ARM GDB
brew tap ArmMbed/homebrew-formulae
brew install arm-none-eabi-gcc

# Press F5 in VS Code to build and debug

The project includes .vscode/launch.json configured for OpenOCD debugging.

Method 4: st-flash

Using ST-Link utilities directly:

# Install stlink tools
brew install stlink

# Build
cargo build --release --target thumbv7em-none-eabihf

# Convert to binary
cargo objcopy --release --target thumbv7em-none-eabihf -- -O binary target/thumbv7em-none-eabihf/release/stm32f303re-blink firmware.bin

# Flash
st-flash write firmware.bin 0x8000000

Dependencies Note

The Cargo.toml uses published Embassy crates from crates.io:

• embassy-stm32 = "0.4.0"
• embassy-executor = "0.9.1"
• embassy-time = "0.5.0"

Key Features

1. Async/Await: LED blink runs asynchronously using Embassy timers
2. Type Safety: Rust's type system prevents many common embedded bugs
3. No Blocking Loops: Uses embassy_time::Timer for clean delay handling
4. UART Logging: Real-time status messages via ST-Link VCP

Serial Output

Connect to the virtual COM port to see status messages:

# macOS
screen /dev/tty.usbmodem* 115200

# Linux
screen /dev/ttyACM0 115200

Output example:

LED ON
LED OFF
LED ON
LED OFF

Generate API Documentation

cargo doc --no-deps --document-private-items --open

Memory Layout

• FLASH: 512KB starting at 0x08000000
• RAM: 64KB starting at 0x20000000

Defined in memory.x for the STM32F303RET6.

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License

MIT