Rust on ESP for FreeBSD

Updated: October 31, 2024

I have been working on FreeBSD ports of Rust on ESP. In addition to C/C++ tool-chains, trombik/xtensa-esp32-elf includes the following Rust on ESP ports.

• lang/rust-esp
• lang/rust-esp-src
• devel/esp-llvm-embedded-toolchain
• devel/esp-llvm-embedded-toolchain-libs-clang
• devel/espflash
• emulators/qemu-esp
• emulators/wokwi-server

espup — rustup for ESP — has not been ported. The tool is sort of “a package manager for rust tool-chains” to switch Rust versions. Currently, I don’t think it is necessary for me.

With these ports, you can follow instructions on The Rust on ESP book. The ported packages can successfully compile Both of “bare-metal” (no_std), and “esp-idf” (std) projects. Some environment variables must be configured. Here is my script to set environment variables for esp-idf and Rust on ESP. To compile them, clone the repository and create an overlay with poudriere(8).

The Rust on ESP book is a great book in addition to The Embedded Rust Book.

Here is my favourite links to learn Rust on ESP:

• ESP32 Standard Library Embedded Rust: GPIO Control
• ESP32 with Embedded Rust at the HAL
• Edge IoT with Rust on ESP: Connecting WiFi
• Awesome ESP Rust

My impression about Rust

It certainly excels at what it promises; type safety and memory safety. String is easier to handle. Library management is a bit tricky sometimes. It requires you to understand new ideas; lifetime and ownership. I like the Rust project provides standard tools; you don’t have to choose tools to use for library management or code formatter. Supporting different architectures is easier and less messy. I’m still learning, but Rust looks very fun to play with.

The state of Rust on ESP is more than what you expect but less than what you hoped for. esp-idf has extensive documentations. With decent C knowledge, it is not difficult to write an application by following the official documentation. In case of Rust on ESP, library reference manuals are a bit sparse. However, Espressif has been investing on Rust for years. I am sure that they will create ones as nice as esp-idf.