maik93 / timesaver_stm32

Just a cooking timer (or a Pomodoro timer, if you want), but written in Rust!

TimeSaver project for STM32F7x7 boards

Basically, this is an implementation for a cooking timer, where an encoder is used to set desired minutes and an internal counter waits this given time, until an alarm is displayed.

More technically, this is a Rust embedded project that deals with a 16x2 character LCD, an encoder (handled with external interrupts) and a timer interrupt that dictate system events. A simple state machine goes through an initial splash screen, then the counter setup, the actual countdown and finally the alarm.

Dependencies

Required target is thumbv7em-none-eabihf, nightly. It is automatically set up thourgh rust-toolchain.toml.

cargo install cargo-embed

Build and upload

Project can be build with cargo build, or build and uploaded with cargo embed. Serial RTT channels can be opened with cargo embed --config with_rtt. Note that somehow it does not work on Clion terminals.

Debug

Breakpoint debug can be achieved with a VSCode plugin, probe-rs-debugger. Install it with:

# VSC plugin (check for new releases here: https://github.com/probe-rs/vscode/releases)
wget https://github.com/probe-rs/vscode/releases/download/v0.4.0/probe-rs-debugger-0.4.0.vsix
code --install-extension probe-rs-debugger-0.3.3.vsix

# debugger server
cargo install --force --git https://github.com/probe-rs/probe-rs probe-rs-debugger

The target board can be then debugged through VSCode, thanks to .vscode/launch.json file. Further details on how to edit this file can be found in the official documentation.

References

Base project configuration for STM32F7x7 boards can be obtained from rust-embedded/cortex-m-quickstart template:

cargo generate rust-embedded/cortex-m-quickstart

Main references used to achive this project:

• cortex-m-quickstart starting template.
• Cargo-embed documentation for upload and serial debug.
• memory.x files from https://github.com/stm32-rs/stm32f7xx-hal.
• stm32f7xx-hal examples
• rtt_target Crate: target side implementation of the Real-Time Transfer I/O protocol.
• probe-rs-debugger plugin for VS-Code