OSEPP Arduino Basics in Rust 🦀

Background

These projects served as a way to introduce myself to embedded Rust and re-introduce myself to Arduino programming. Each of these is a translation of a project in the long discontinued OSEPP Arduino Basics Starter Kit. There is nothing unique about this kit except that I already had it sitting at my desk drawer. Most of these projects are similar to examples in the Arduino IDE, and they should work on any Arduino hardware.

These projects were created using the excellent Rahix/avr-hal-template. This template is very simple, and highly recommended for quickly getting started with Rust programming on Arduino.

General Observations

All of these projects were translated from Arduino sketches provided with the OSEPP kit. In many cases, the original C code could be translated almost verbatim. However, there are some differences in the way that the hardware is exposed in arduino-hal compared to the original SDK. Most notably, all pins are accessed via struct fields, rather than simple byte or int parameters on function calls. The obvious benefit here is the additional safety provided at compile time. In some cases though, pins are iterated. Since the fields cannot be iterated directly, the pins are placed into an array and the array is iterated.

Project Descriptions

Below is a description of each project, as well as a link to the corresponding OSEPP tutorial which contains a more in-depth description as well as schematics and wiring diagram.

tutorial2-digital-outputs (docs) - Use digital output signals to control an array of 4 LEDs.
tutorial3-digital-input (docs) - Use digital input to read the state of a tact switch and report over the serial port monitor.
tutorial4-led-game (docs) - Combine digital input and output signals to create a simple game using LEDs and a tact switch.
tutorial5-voltage-meter (docs) - Build a simple voltage divider circuit and report output voltage over the serial port monitor.
tutorial6-buzzer-melody (docs) - Use digital output and a buzzer to play a melody.
- Note: The original implementation for this circuit relies on the tone() function in the Arduino SDK. Rather than attempt to re-implement the tone function, it is simulated using delay_us(). In the future, it might be interested to try implementing the tone function using interrupts in Rust.
tutorial7-7segment-countdown (docs) - Use digital outputs to display a countdown from 9 to 0 on a 7 segment LED display

Usage

If you don't have it already, install ravedude:

cargo install ravedude

These projects are configured to target the OSEPP Uno R3 Plus board which uses the old nano bootloader. To target different hardware, you will need to change the features on the arduino-hal and avr-device dependencies.

[dependencies.arduino-hal]
git = "https://github.com/rahix/avr-hal"
rev = "533159f6c6a508abe4ecec34bf5013d7a1eb0cf5"
features = ["arduino-nano"]

[dependencies.avr-device]
version = "0.4"
features = ["atmega328p", "rt"]

Note: Most projects only depend on arduino-hal. The following options are supported by arduino-hal at this time. If using a different board, replace the arduino-nano feature string with the string corresponding to your board.

"Adafruit Trinket" - trinket
"Adafruit Trinket Pro" - trinket-pro
"Arduino Leonardo" - arduino-leonardo
"Arduino Mega 2560" - arduino-mega2560
"Arduino Mega 1280" - arduino-mega1280
"Arduino Nano" - arduino-nano
"Arduino Nano New Bootloader" - arduino-nano
"Arduino Uno" - arduino-uno
"SparkFun ProMicro" - sparkfun-promicro
"Nano168" - nano168

Valid options for the chip feature in avr-device are as follows:

atmega32u4
atmega48p
atmega168
atmega328p
atmega1280
atmega2560
attiny85
attiny88

To run the projects, you will need to set the RAVEDUDE_PORT environment variable to the serial port on your system. See the ravedude README for more advanced configuration options. Finding the serial port on your system is outside the scope of this document. In general, USB serial ports on linux will start with /dev/ttyUSB and on macOS will start with /dev/tty.usbserial.

For example, to run the tutorial2-digital-outputs project:

cd tutorial2-digital-outputs
export RAVEDUDE_PORT=/dev/tty.usbserial-ABC123
cargo run

License

Licensed under MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

Contribution

This repo was created simply to document a personal project, but feel free to submit issues/MRs to address any errors found.