Rust on a $2 dev board

Rust is a great option for embedded computing, especially for small devices like ESP32.

There is a very inexpensive dev board, called ESP32-C3 Super Mini which sells for ~$2 on AliExpress.

The chip is RISC-based, supports Wifi & Bluetooth, and includes a built-in LED - which we'll use in this project.

Installing Rust

First you'll need Rust on your machine.

The toolchain can be installed via Rustup, or (my preferred way) using asdf.

TIP: asdf is a great way to manage multiple versions of programming language tools.

To install with asdf:

# add rust plugin
asdf plugin-add rust https://github.com/asdf-community/asdf-rust.git

# install rust
asdf install rust 1.81.0

# set default version
asdf global rust 1.81.0

Create the project

Let's create the project folder structure.

We can start with the template:

$> cargo generate esp-rs/esp-idf-template cargo

⚠️   Favorite `esp-rs/esp-idf-template` not found in config, using it as a git repository: https://github.com/esp-rs/esp-idf-template.git
🤷   Project Name: blink
🔧   Destination: some/path/blink ...
🔧   project-name: blink ...
🔧   Generating template ...
✔ 🤷   Which MCU to target? · esp32c3
✔ 🤷   Configure advanced template options? · false
🔧   Moving generated files into: `some/path/blink`...
🔧   Initializing a fresh Git repository
✨   Done! New project created some/path/blink

We'll need access to the HAL (hardware abstraction layer), so install the esp-idf-hal crate too:

cd blink
cargo add esp-idf-hal

The Code

Now add this to src/main.rs to blink the LED:

use esp_idf_hal::delay::FreeRtos;
use esp_idf_hal::gpio::*;
use esp_idf_hal::peripherals::Peripherals;
use log::info;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // enable logging
    esp_idf_svc::log::EspLogger::initialize_default();

    // get peripherals
    let peripherals = Peripherals::take()?;

    // built-in LED is GPIO8
    let mut led = PinDriver::output(peripherals.pins.gpio8)?;

    // alternate between high and low, with delay of 1s
    loop {
        info!("high");
        led.set_high()?;
        FreeRtos::delay_ms(1000);

        info!("low");
        led.set_low()?;
        FreeRtos::delay_ms(1000);
    }
}

Running the code

Connect the dev board to USB, and then flash it with:

cargo run

The LED should now be blinking, and the message "HIGH"/"LOW" will be displayed in the terminal.

Happy hacking ✌️

P.S. Here's the source code:
https://github.com/joshnuss/esp-blink-rs