Nix flake and overlay for developing for WCH MCUs.

This tool is a work in progress.

This flake provides packages and tools to make development for WCH MCUs easier. Moreover, it consists of Nix functions to make package and shell creation more convenient.

To create a package, one can use the mkWCHProject Nix function. It has the following parameters:

• pname - package name
• version - package version
• src - path to the source code
• mcu - MCU's name (e.g. ch58x)
• toolchain - one of the toolchain packages
• debug - whether to enable debug build or not (default: true)

Additionally, one can use mkWCHShell Nix function to create a shell. Its parameters are:

• name - shell name
• mcu - MCU's name (e.g., "ch58x")
• toolchain - one of toolchain packages

Shells:

• ch58x

Tools:

• wchisp

Supported toolchains:

• default - RISC-V GNU Compiler Toolchain. Used when field is unspecified
• riscv-none-elf-gcc-xpack - The xPack GNU RISC-V Embedded GCC
• mrs-toolchain - MounRiver studio toolchain

To enter a simple predefined shell:

nix develop github:azazak123/nixpkgs-wch-dev#ch58x

Package definition:

packages.example = pkgs.mkWCHProject {
  pname = "example";
  version = "1";
  src = ./.;
  debug = false;
  mcu = "ch58x";
};

Example of a simple flake.nix file:

{
  inputs = {
    nixpkgs.url = "nixpkgs/nixpkgs-unstable";
    nixpkgs-wch-dev.url = "github:azazak123/nixpkgs-wch-dev";
  };

  outputs =
    { self, nixpkgs, nixpkgs-wch-dev }:
    let
      pkgs = nixpkgs.legacyPackages.x86_64-linux.extend (nixpkgs-wch-dev.overlays.default);
    in
    {
      packages.x86_64-linux.default = pkgs.mkWCHProject {
        pname = "example";
        version = "0.1";
        src = ./.;
        debug = false;
        mcu = "ch58x";
      };

      devShells.x86_64-linux = {
        default = nixpkgs-wch-dev.devShells.x86_64-linux.ch58x;
      };
    };
}

A more complicated example can be found in the examples folder. It has a blink program that includes a simple project structure example with a source folder, flake.nix, and CMakeLists.txt.

For now, I only have ch58x unfortunately. As my collection grows, I will add new MCUs.

• ch58x

Here are some projects that I used and took inspiration from. Many thanks to their developers!

• https://github.com/mirrexagon/nixpkgs-esp-dev
• https://github.com/MatthewCroughan/nrf-nix
• https://github.com/rgoulter/ch592-ble-hid-keyboard-example
• https://github.com/ohmytime/CH58X-CMake

Contributions to nixpkgs-wch-dev are welcome! Whether you are fixing a bug, adding new features, improving documentation, or providing feedback, your input helps improve this project!