m5unified-rs

Rust bindings for M5Unified, the board support library used across M5Stack ESP32 devices.

The project publishes two crates:

m5unified - safe Rust API for common M5Unified display, button, microphone, speaker, IMU, touch, RTC, power, log, and SD-card operations.
m5unified-sys - raw FFI declarations plus the C/C++ ESP-IDF component shim used by the safe crate.

The binding strategy is intentionally narrow: Rust calls a plain extern "C" shim instead of trying to bind the full M5Unified C++ class surface directly.

Install

For applications, depend on the safe wrapper:

[dependencies]
m5unified = "0.1"

Use m5unified-sys directly only when writing lower-level bindings or firmware integration code that needs the raw C ABI.

Quick Start

use m5unified::{colors, M5Unified};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut m5 = M5Unified::begin()?;

    m5.display.fill_screen(colors::BLACK);
    m5.display.set_text_size(2);
    m5.display.println("hello from Rust")?;

    loop {
        m5.update();
        if m5.buttons.a().was_pressed() {
            m5.display.println("Button A")?;
        }
        m5.delay_ms(16);
    }
}

Target Support

On ESP-IDF targets, m5unified-sys declares the C ABI that is implemented by the native shim in this repository. Firmware projects should include that shim as an ESP-IDF component so the Rust crate links against the real M5Unified and M5GFX libraries.

On non-ESP-IDF host targets, m5unified-sys provides no-op Rust stubs. This keeps the safe wrapper and translated examples buildable in CI and on developer machines without M5Stack hardware. Host stubs are for compile-time checking, not hardware simulation.

API Surface

The current wrapper covers the API used by the translated upstream examples:

display drawing, text, color, brightness, transactions, and multi-display access
button press, release, hold, click, and click-count state
microphone recording helpers and simple RMS calculation
speaker tone, PCM, WAV, channel, and volume controls
IMU acceleration, gyro, temperature, calibration, and NVS offsets
touch points and touch detail state
RTC date/time, power/battery, AXP2101 IRQ helpers, logging, and SD begin

This is not a complete M5Unified port yet. Missing APIs should be added through the C ABI shim first, then wrapped by m5unified.

Repository Layout

crates/
  m5unified-sys/   raw bindings and native C/C++ shim
  m5unified/       safe Rust wrapper
examples/          host-checkable Rust ports of upstream M5Unified examples
firmware/          ESP-IDF Rust firmware package for hardware validation
docs/              example mapping, project plans, and release notes

Examples

Rust translations and smoke ports of upstream M5Unified examples live in the repository's examples workspace package. They are intentionally not published as a crate.

bash scripts/check-host.sh
cargo run -p m5unified-examples --bin basic_displays

See the repository docs for the upstream-to-Rust example mapping and firmware bring-up instructions.

Firmware Bring-Up

The first ESP-IDF Rust firmware package lives at firmware/hello-display in the repository. It is excluded from the host workspace because it requires the esp-rs xtensa-esp32s3-espidf toolchain.

Install the esp-rs tools before building firmware:

cargo +stable install espup
espup install
. ~/export-esp.sh
cargo +stable install espflash

Then build and flash the sample firmware:

cd firmware/hello-display
cargo build --target xtensa-esp32s3-espidf
espflash flash --monitor target/xtensa-esp32s3-espidf/debug/m5unified-hello-display

Expected hardware behavior: the display shows hello from rust; Button A/B presses change the screen.

Release Checks

python3 tools/check_examples_manifest.py
python3 tools/check_no_sys_in_examples.py
bash scripts/check-host.sh
cargo package -p m5unified-sys
cargo publish -p m5unified-sys --dry-run

Publish m5unified-sys before m5unified, because the safe crate depends on the exact sys crate version through crates.io. Package and dry-run m5unified after the sys crate upload has propagated. See docs/publishing.md in the repository for the full release checklist.

License

Licensed under either MIT or Apache-2.0, at your option.

m5unified-sys 0.1.0