Adafruit ItsyBitsy M4 Express Board Support Crate

This crate provides a type-safe Rust API for working with the Adafruit ItsyBitsy M4 Express board.

Board Features

• Microchip [ATSAMD51G] Cortex-M4 microcontroller @ 120 MHz (32-bit, 3.3V logic and power)
  • 512kB Flash
  • 192kB SRAM
• 2 MB SPI Flash chip

Prerequisites

• Install the cross compile toolchain rustup target add thumbv7em-none-eabihf
• Install cargo-hf2 the hf2 bootloader flasher tool however your platform requires

Uploading an example

Check out the repository for examples:

https://github.com/atsamd-rs/atsamd/tree/master/boards/itsybitsy_m4/examples

• Be in this directory cd boards/itsybitsy_m4
• Put your device in bootloader mode usually by hitting the reset button twice.
• Build and upload in one step

$ cargo hf2 --release --example blinky_basic
    Finished release [optimized + debuginfo] target(s) in 0.19s
    Searching for a connected device with known vid/pid pair.
    Trying  Ok(Some("Adafruit Industries")) Ok(Some("PyBadge"))
    Flashing "/Users/User/atsamd/boards/itsybitsy_m4/target/thumbv7em-none-eabihf/release/examples/blinky_basic"
    Finished in 0.079s
$

Note some examples will tell you they need more features enabled

$ cargo hf2 --release --example usb_serial
error: target `usb_serial` in package `itsybitsy_m4` requires the features: `usb`
Consider enabling them by passing, e.g., `--features="usb"`

Just follow the instructions to add --features like

cargo hf2 --release --example usb_serial --features="usb"
    Finished release [optimized + debuginfo] target(s) in 0.09s
    Searching for a connected device with known vid/pid pair.
    Trying  Ok(Some("Adafruit Industries")) Ok(Some("PyBadge"))
    Flashing "/Users/User/atsamd/boards/itsybitsy_m4/target/thumbv7em-none-eabihf/release/examples/usb_serial"
    Finished in 0.167s
$

If you are on Linux and hf2 fails to flash your board even if it is connected and in bootloader mode, you might need to add some udev rules if you have not done that yet.

The example for adafruit boards is shown here.

You might want to have all the hf2 related rules in a single file, i.e. /etc/udev/rules.d/99-hf2-boards.rules, or have a different rules file for each vendor. The rules for Adafruit boards look like this:

#adafruit rules
ATTRS{idVendor}=="239a", ENV{ID_MM_DEVICE_IGNORE}="1"
SUBSYSTEM=="usb", ATTRS{idVendor}=="239a", MODE="0666"
SUBSYSTEM=="tty", ATTRS{idVendor}=="239a", MODE="0666"

After adding the rules remember to reboot or run:

sudo udevadm control --reload-rules
sudo udevadm trigger

For more information on hf2 and other methods of uploading your code, take a look at the base project README.