Rust bindings for ESP-IDF (Espressif's IoT Development Framework)

Background

The ESP-IDF API in Rust, with support for each ESP chip (ESP32, ESP32S2, ESP32C3 etc.) based on the Rust target

Build

• The build requires the Rust ESP32 STD compiler fork to be configured and installed as per the instructions there.
• The relevant Espressif toolchain, as well as the esp-idf itself are all automatically downloaded during the build by
  • with the feature pio (default): utilizing platformio (via the embuild crate) or
  • with the feature native (experimental): utilizing native esp-idf tooling.
• Check the mini crate for a "Hello, world!" Rust template demonstrating how to use and build this crate
• Check the demo crate for a more comprehensive example in terms of capabilities

Feature pio

This is currently the default for installing all build tools and building the ESP-IDF framework. It uses PlatformIO via the embuild crate.

Feature native

This is an experimental feature for downloading all tools and building the ESP-IDF framework using the framerosk's "native" own tooling. It will become the default in the near future. It also relies on build and installation utilities available in the embuild crate.

Currently, this build script installs all needed tools to compile the esp-idf as well as the esp-idf itself using embuild::espidf::Installer. There are two locations where the esp-idf source and tools are detected and installed:

• ~/.espressif
• $ESP_IDF_INSTALL_DIR or <crate workspace-dir>/.embuild/espressif

Bluetooth Support

In order to enable Bluetooth support with either Bluedroid or NimBLE, there is some additional work:

• Go to the root of your binary crate project (e.g., the "Hello, World" demo)
• Create a .cargo/config.toml file if it does not exist there yet. You can copy it from the "Hello, World" demo
• Include in it the following:

[env]
...
ESP_IDF_SYS_GLOB_0 = { value = "/sdkconfig" }

• Next, create a file sdkconfig at the root of binary crate your project. This could be generated with cargo pio espidf menuconfig if you install cargo-pio (see below) but a minimal manual example follows:

CONFIG_BT_ENABLED=y
CONFIG_BTDM_CTRL_MODE_BLE_ONLY=y
CONFIG_BTDM_CTRL_MODE_BR_EDR_ONLY=n
CONFIG_BTDM_CTRL_MODE_BTDM=n
// Uncomment whichever of these you need
//CONFIG_BT_BLUEDROID_ENABLED=y
//CONFIG_BT_NIMBLE_ENABLED=y

Using cargo-pio to interactively modify ESP-IDF's sdkconfig file

To enable Bluetooth, or do other configurations to the ESP-IDF sdkconfig you might take advantage of the cargo-pio Cargo subcommand:

• To install it, issue cargo install cargo-pio --git https://github.com/ivmarkov/cargo-pio
• To open the ESP-IDF interactive menuconfig system, issue cargo pio espidf menuconfig in the root of your binary crate project
• To use the generated/updated sdkconfig file, follow the steps described in the "Bluetooth Support" section

More info

If you are interested how it all works under the hood, check the build.rs build script of this crate.

Requirements

• If using chips other than esp32c3:
  • Rust ESP32 compiler fork
  • libclang of the xtensa LLVM fork
• python >= 3.7

Configuration

Environment variables are used to configure how the esp-idf is compiled. The following environment variables are used by the build script:

• ESP_IDF_INSTALL_DIR:

  The path to the directory where all esp-idf tools are installed. If it is set to a relative path, it is relative to the crate workspace-dir.

  If not set, when ESP_IDF_GLOBAL_INSTALL is set to 1 it defaults to the global install dir ~/.espressif, otherwise it defaults to the local install dir <crate workspace-dir>/.embuild/espressif.

• ESP_IDF_GLOBAL_INSTALL

  If set to 1, true, y or yes uses the global install directory only when ESP_IDF_INSTALL_DIR is not specified.

• ESP_IDF_VERSION: The version used for the esp-idf can be one of the following:

  • commit:<hash>: Uses the commit <hash> of the esp-idf repository. Note that this will clone the whole esp-idf not just one commit.
  • tag:<tag>: Uses the tag <tag> of the esp-idf repository.
  • branch:<branch>: Uses the branch <branch> of the esp-idf repository.
  • v<major>.<minor> or <major>.<minor>: Uses the tag v<major>.<minor> of the esp-idf repository.
  • <branch>: Uses the branch <branch> of the esp-idf repository.

  It defaults to v4.3.

• ESP_IDF_REPOSITORY: The URL to the git repository of the esp-idf, defaults to https://github.com/espressif/esp-idf.git.

• ESP_IDF_SDKCONFIG_DEFAULTS: A ;-separated list of paths to sdkconfig.default files to be used as base values for the sdkconfig.

• ESP_IDF_SDKCONFIG: A path (absolute or relative) to the esp-idf sdkconfig file.

• MCU: The mcu name (e.g. esp32 or esp32c3). If not set this will be automatically detected from the cargo target.