Rust on the ESP32 of the MCH2022 badge

• Install Rust toolchain from https://github.com/esp-rs/rust-build:

  git clone https://github.com/esp-rs/rust-build.git
  cd rust-build
  ./install-rust-toolchain.sh --extra-crates "ldproxy cargo-espflash wokwi-server web-flash" \
    --export-file /home/<user>/export-esp.sh \
    --esp-idf-version "release/v4.4" \
    --minified-esp-idf "YES" \
    --build-target "esp32" \
  source /home/<user>/export-esp-rust.sh  
  

• Install cargo-generate:

  cargo install cargo-generate
  

• Install the mch2022 webusb tools from https://github.com/badgeteam/mch2022-tools:

  pip install pyusb
  

• Create a new project as follows:

cargo generate --git https://github.com/esp-rs/esp-idf-template cargo
cd <project-name>

• You can generate an app image using:

cargo espflash ESP32 save-image main.bin

• This image can then be uploaded to the badge as follows:

webusb_push.py --run rust main.bin

• The image can also be uploaded to the hatchery as a native ESP32 application
• println! output appears on the first serial port exposed by the MCH022 badge
• If your program panics, the badge will reboot to the main menu, use the serial port to see any panic related messages.
• All crates which work on ESP32 should be available
• When using devcontainers, it supports Wokwi simulation:

Limitations

• These instructions use the esp-idf as provided by Espressif so you won't have access to the components added by the badge team. It's probably possible to use their version, but I have not tried this.

Example code

• The code is a quick hack but should give you an idea on what you can do.

Known issues

• There's no VSYNC easily available so the icon doesn't move as smooth as it should
• Drawing is rather slow probably because of the SPI interface and the overhead of using the embedded_graphics crate. Maybe writing a dedicated driver for controlling the display would result in better performance.

Dev Containers

This repository offers ready-to-use devlopment environments via Dev Containers for:

• Gitpod
• VS Code Dev Containers
• GitHub Codespaces

Note

In order to use GitHub Codespaces the project needs to be published in a GitHub repository and the user needs to be part of the Codespaces beta or have the project under an organization.

If using VS Code or GitHub Codespaces, you can pull the image instead of building it from the Dockerfile by selecting the image property instead of build in .devcontainer/devcontainer.json. Further customization of the Dev Container can be achived, see .devcontainer.json reference.

When using Dev Containers, some tooling to facilitate building, flashing and simulating in Wokwi is also added.

Build

• Terminal approach:

  scripts/build.sh  [debug | release]
  

  If no argument is passed, release will be used as default

• UI approach:

  The default build task is already set to build the project, and it can be used in VS Code and Gitpod:

  • From the Command Palette (Ctrl-Shift-P or Cmd-Shift-P) run the Tasks: Run Build Task command.
  • Terminal-> Run Build Task in the menu.
  • With Ctrl-Shift-B or Cmd-Shift-B.
  • From the Command Palette (Ctrl-Shift-P or Cmd-Shift-P) run the Tasks: Run Task command and select Build.
  • From UI: Press Build on the left side of the Status Bar.

Flash

At the momment there is no way to flash the Badge from the containers

Wokwi Simulation

When using a custom Wokwi project, please change the WOKWI_PROJECT_ID in run-wokwi.sh. If no project id is specified, a DevKit for esp32 will be used.

Warning

ESP32-S3 is not available in Wokwi

• Terminal approach:

  scripts/run-wokwi.sh [debug | release]
  

  If no argument is passed, release will be used as default

• UI approach:

  The default test task is already set to build the project, and it can be used in VS Code and Gitpod:

  • From the Command Palette (Ctrl-Shift-P or Cmd-Shift-P) run the Tasks: Run Test Task command
  • With Ctrl-Shift-, or Cmd-Shift-,

    Note

    This Shortcut is not available in Gitpod by default.

  • From the Command Palette (Ctrl-Shift-P or Cmd-Shift-P) run the Tasks: Run Task command and select Build & Run Wokwi.
  • From UI: Press Build & Run Wokwi on the left side of the Status Bar.

Warning

The simulation will pause if the browser tab is in the background.This may affect the execution, specially when debuging.

Debuging with Wokwi

Wokwi offers debugging with GDB.

• Terminal approach:

  $HOME/.espressif/tools/xtensa-esp32-elf/esp-2021r2-patch3-8.4.0/xtensa-esp32-elf/bin/xtensa-esp32-elf-gdb target/xtensa-esp32-espidf/debug/mch -ex "target remote localhost:9333"
  

  Wokwi Blog: List of common GDB commands for debugging.

• UI approach:

  1. Run the Wokwi Simulation in debug profile
  2. Go to Run and Debug section of the IDE (Ctrl-Shift-D or Cmd-Shift-D)
  3. Start Debugging by pressing the Play Button or pressing F5
  4. Choose the proper user:
     • esp when using VS Code or GitHub Codespaces
     • gitpod when using Gitpod