A platform for creating custom midi controllers.

⚠️ Warning ⚠️ : I use this project to learn rust. It's not meant to be used in production. Expect things to break and code to undergo heavy refactoring.

Background

This is the firmware part of a project that aims to let you create your own midi controllers. Core of this project is an extendible PCB with multiple slots which can accommodate any of a number of different in- and output modules. Muliple PCBs can be daisy-chained to further extend the amount of slots available. For now a YAML file can be used to describe the arrangement of in- and output modules. In the future a web based configurator will be added to assist with this process.

Hardware

In order to reduce the in- and outputs needed on the used microcontroller the hardware is based on daisy-chained analog in- and output multiplexers.

Currently the PCB is designed to support the following in- and outputs:

• Rotary Encoder (EC11 style)
• Analog Fader
• Analog Potentiometer
• WS2812B RGB LEDs

Features

• In-Memory UI backend can emulate all inputs
• Encoder with Midi CC relative and absolute msg support
• Midi Output support
• Device configuration can be saved/loaded using YAML
• All features above are unit- or integration tested

Building

The project can be built for thumbv7m-none-eabi and x86_64-unknown-linux-gnu. The Containerfile bundles both toolchains as well as all the dependencies. To build the container run:

$ podman build -t ctrl-reset-rust .

Run the following to get an interactive shell inside the container:

$ podman container runlabel shell ctrl-reset-rust

To build the binary from there run

# build the stm32-poc
$ cargo build --target thumbv7m-none-eabi --release --features bare-metal --bin stm32-poc

# build the host-poc
$ cargo build --bin reset_ctrl

Flashing

The binary can be flashed from inside the container. If you are working with an SELinux enabled OS make sure to load the corresponding embedded_container.cil file to allow the container access to the STLink programmer:

$ sudo semodule -i embedded_container.cil /usr/share/udica/templates/{base_container.cil,net_container.cil}

Connect your STLink programmer and run the container like this:

$ podman container runlabel shellem ctrl-reset-rust

Now flashing works as expected by running:

$ cargo run --target thumbv7m-none-eabi --release --bin stm32-poc --features bare-metal

Testsing

Most parts of the project are unit- and integration tested. Currently the tests can only be tested on x86_64-unknown-linux-gnu because testing relies on the std crate. To run the tests, start a shell inside the container and run:

$ cargo test

Contributing

In order to do automated releases and changelogs conventional-commits are used. For new features commits are prefix with feat: ... and for bugfixes with: fix: .... Breaking changes are introduced with an ! after the prefix like feat!: ... or fix!: ....

To make sure commits pass the GitHub CI workflow pre-commit can be used. It's contained in the container image. It can be run manually using the command pre-commit run. To use it as an actual git pre-commit hook, copy the hook file utils/hooks/pre-commit to .git/hooks/pre-commit. Make sure the file is executable by your current user. The hook is intended to be used by a git commit made from your host system. It will run pre-commit in a new container. This way you don't have to install any dependencies needed by pre-commit.

Roadmap

As this projects purpose is to learn rust, don't expect any of the features outlined below to be implemented in order or a timely manner.

• Support for linux, wasm and bare metal microcontrollers
• Support for encoder, potentiometer, fader and RGB LEDs
• CLI for configuration