nix-qemu-esp32c3-rust-example

This is an example / test for https://github.com/SFrijters/nix-qemu-espressif; it is kept out of that repository to keep it as lean as possible.

Usage

As an example we compile a simple 'blinking LED' Rust code based on an example in esp-hal for an ESP32C3 chip and run it on QEMU:

• nix flake check -L

This command is also run in the GitHub action.

This flake also provides the following apps:

• nix run .#emulate (default app) to run the emulation test script directly.
• nix run .#flash to flash the compiled code to a physical device.

And a development shell via:

• nix develop

Inside the development shell, we can also use cargo directly to build the binary:

$ nix develop
$ cd blinky && cargo build --release

Finally, there are three package outputs:

• nix build .#elf-binary builds only the ELF binary file.
• nix build .#emulate-script (default package) builds a script to run the emulation test.
• nix build .#flash-script builds a wrapper script to flash the binary to a physical device using espflash.

Physical test

The code has been tested on a Seeed Studio XIAO ESP32C3. The GPIO10 pin corresponds to the D10 pin as marked on the board.

Known issues

This example code works around a linker issue in nixpkgs in blinky/.cargo/config.toml. Please refer to the linked issue for details and please suggest a better/permanent fix if you know of one!

Further reading

• https://github.com/espressif/qemu
• https://github.com/espressif/esp-toolchain-docs/blob/main/qemu/esp32c3/README.md
• https://github.com/esp-rs/esp-hal/
• https://github.com/esp-rs/no_std-training/
• https://n8henrie.com/2023/09/compiling-rust-for-the-esp32-with-nix/