Rust on ESP-IDF “Hello, World” template

A template for a “Hello, world!” Rust binary crate for the ESP-IDF framework. Based on cargo-generate.

This is the crate you get when running cargo new, but augmented with extra configuration so that it does build for the ESP32[XX] with ESP-IDF and (by default) with STD support.

Or if you rather

• … want to mix Rust and C/C++ in a traditional ESP-IDF idf.py CMake project - follow these instructions
• … want to mix Rust and C/C++ with PlatformIO - follow these instructions

For more check out the links in the additional information seciton

Generate the project

Please make sure you have installed all prerequisites first!

cargo generate esp-rs/esp-idf-template cargo

The command will display a few prompts:

• Project Name: Name of the crate.
• Which MCU to target?: SoC model, e.g. esp32, esp32s2, esp32c3 etc.
• Configure advanced template options?: If false, skips the rest of the prompts and uses their default value. If true, you will be prompted with:
  • Enable STD support?: When true (default), adds support for the Rust Standard Library. Otherwise, a no_std Rust Core Library crate would be created.
  • ESP-IDF Version: ESP-IDF branch/tag to use. Possible choices:
    • v4.4: Stable
    • v5.1: Stable
    • master: Unstable
  • Configure project to support Wokwi simulation with Wokwi VS Code extension?: Adds support for Wokwi simulation using VS Code Wokwi extension.
  • Configure project to use Dev Containers (VS Code and GitHub Codespaces)?: Adds support for:
    • VS Code Dev Containers
    • GitHub Codespaces Dev Containers also allow flashing from the container using web flash and have the VS Code Wokwi extension already installed.

Build

cd <your-project-name>
cargo build

• Replace <your-project-name> with the name of the generated project

Flash

In the root of the generated project:

espflash /dev/ttyUSB0 target/[xtensa-esp32-espidf|xtensa-esp32s2-espidf|xtensa-esp32s3-espidf|riscv32imc-esp-espidf]/debug/<your-project-name>

• Replace dev/ttyUSB0 above with the USB port where you’ve connected the board. If you do not specify any USB port, espflash will print a list of the recognized USB ports for you to select the desired port.
• Replace <your-project-name> with the name of the generated project
• You can include the --monitor argument to the espflash command to open a serial monitor after flashing the device.
• For more details on espflash usage see the README

Monitor

espflash monitor /dev/ttyUSB0

• Replace dev/ttyUSB0 above with the USB port where you’ve connected the board. If you do not specify any USB port, cargo-espflash/espflash will print a list of the recognized USB ports for you to select the desired port.

The monitor should output more or less the following:

Opening /dev/tty.usbserial-0001 with speed 115200
Resetting device... done
ets Jun  8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0048,len:12
ho 0 tail 12 room 4
load:0x3fff0054,len:4800
load:0x40078000,len:17448
load:0x4007c428,len:4840
entry 0x4007c6a0
I (178) cpu_start: Pro cpu up.
I (178) cpu_start: Starting app cpu, entry point is 0x4008115c
I (0) cpu_start: App cpu up.
I (193) cpu_start: Pro cpu start user code
I (193) cpu_start: cpu freq: 160000000
I (193) cpu_start: Application information:
I (197) cpu_start: Project name:     esp-idf
I (202) cpu_start: App version:      f08dcd7
I (207) cpu_start: Compile time:     Oct 23 2021 14:48:03
I (213) cpu_start: ELF file SHA256:  0000000000000000...
I (219) cpu_start: ESP-IDF:          4.3.0
I (224) heap_init: Initializing. RAM available for dynamic allocation:
I (231) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM
I (237) heap_init: At 3FFB3498 len 0002CB68 (178 KiB): DRAM
I (243) heap_init: At 3FFE0440 len 00003AE0 (14 KiB): D/IRAM
I (250) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (256) heap_init: At 4008C538 len 00013AC8 (78 KiB): IRAM
I (263) spi_flash: detected chip: generic
I (267) spi_flash: flash io: dio
I (272) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.
Hello, world!

Additional information

For more information, check out:

• The Rust on ESP Book
• The ESP STD Embedded Training
• The esp-idf-hal project
• The embedded-hal project
• The esp-idf-svc project
• The embedded-svc project
• The esp-idf-sys project
• The Rust for Xtensa toolchain
• The Rust-with-STD demo project

Prerequisites

For detailed instructions see Setting Up a Development Environment chapter of The Rust on ESP Book.

Install Rust (with rustup)

If you don’t have rustup installed yet, follow the instructions on the rustup.rs site

Install Cargo Sub-Commands

cargo install cargo-generate
cargo install ldproxy
cargo install espup
cargo install espflash
cargo install cargo-espflash # Optional

Note

If you are running macOS or Linux then libuv must also be installed for espflash and cargo-espflash; this is available via most popular package managers. If you are running Windows you can ignore this step.

# macOS
brew install libuv
# Debian/Ubuntu/etc.
apt-get install libuv-dev
# Fedora
dnf install systemd-devel

Also, the espflash and cargo-espflash commands shown below, assume that version 2.0 or greater.

Install Rust & Clang toolchains for Espressif SoCs (with espup)

espup install
# Unix
. $HOME/export-esp.sh
# Windows
%USERPROFILE%\export-esp.ps1

Warning

Make sure you source the generated export file, as shown above, in every terminal before building any application as it contains the required environment variables.

See the Installation chapter of The Rust on ESP Book for more details.

Alternative (for RISC-V Espressif SOCs only): install & use upstream nightly Rust and upstream stable Clang

While you can target the RISC-V Espressif SOCs (esp32-cXX and esp32-hXX) with the espup installer just fine, SOCs with this architecture are also supported by the nightly Rust compiler and by recent, stock Clang compilers (as in Clang 11+):

• Install a recent Clang. See Clang Getting Started page as it contains useful guidelines on instalaltion. Recent Linux distros come with suitable Clang already.
• Install the nightly Rust toolchain with the rust-src component included:

  rustup toolchain install nightly --component rust-src

• Run any Cargo command with the nightly toolchain override, i.e. cargo +nightly ....

Install Python3

You need a Python 3.7 or later installed on your machine.

• Linux, Mac OS X: if not preinstalled already, just install it with your package manager
• Windows: install it e.g. from the official Python site.