Embedded Rust on SAMD/E microcontrollers gets way better #Rust @MicrochipMakes @RustLang @RustEmbedded

Rust (rustlang) on the Microchip SAMD51 Adafruit Metro M4 microcontroller board!

Since Adafruit has last blogged about using Rust on Microcontroller Boards, the ecosystem has made some terrific improvements.

New board support: We have board support crates for a huge number of Adafruit and common dev boards over at https://github.com/atsamd-rs/atsamd/tree/master/boards. Each of these implement a crate that provides the pinout as its own type, configured the memory layout, and frequently a number of the features of the board (such as USB, UART, SPI displays, SD cards, dotstar LEDs etc) are wired as well.

The most complete of these is the Pygamer BSP. These BSPs typically get added to as contributors get hardware, so the more common boards / boards-which-contributors-own have the best support and most peripherals wired up.

Flashing from rust: A new tool is hf2, which lets you build and upload to a board in a single command, all from within the Rust ecosystem! On Linux, it is as simple as:

cargo install cargo-hf2
cargo hf2 --release

To flash the module in the working directory to a chip with a UF2 bootloader.

Native USB device support: There is first-class support for the USB peripheral in samd21 and samd/e 5x chips. Rust really shines here: because of the implemented UsbBus trait, any UsbClass implementation can work out of the box. For instance, anyone can just wire usbd-serial to get a USB serial implementation, as this itsybitsy_m4 example does. Or wire usbd-hid to get a USB mouse/keyboard.

Ecosystem-wide HAL traits are making good headway:

  • embedded_hal (canonical HAL traits, but slow to change/add by necessity) continues to make slow progress with general purpose HAL abstractions that can be shared across different boards/chips/no-std implementations. At this stage, the interface for GPIO pins, SPI, I2C, watchdogs, and timers are reasonably complete, enabling chip crates like atsamd to provide implementations, and other crates to implement drivers for a remote chip (and have it just work, regardless of the chip in question).
  • For example, there is SDCard support by wiring the SPI trait, which then get consumed by the embedded-sdmmc crate to implement filesystem access.
  • Graphics are awesome – embedded_graphics crate, coupled through traits with drivers for the specific display (ie: ili9341-rs)

See more on GitHub here.

Read more »