# Adafruit NeoTrellis M4 Express Board Support Crate

This crate provides a type-safe Rust API for working with the
[Adafruit NeoTrellis M4 board].

![Adafruit NeoTrellis M4](https://cdn-shop.adafruit.com/970x728/3938-05.jpg)

## Board Features

- Microchip [ATSAMD51G] Cortex-M4 microcontroller @ 120 MHz (32-bit, 3.3V logic and power)
  - 512kB Flash
  - 192kB SRAM
- 8 MB SPI Flash chip
- USB device controller (for e.g. MIDI)
- 4-JST hacking port with 3.3V power, ground, and two GPIO (can be I2C/ADC/UART)
- Analog Devices [ADXL343] triple-axis accelerometer

## Prerequisites
* Install the cross compile toolchain `rustup target add thumbv7em-none-eabihf`
* Install [cargo-hf2 the hf2 bootloader flasher tool](https://crates.io/crates/cargo-hf2) however your platform requires

## Uploading an example
Check out the repository for examples:

https://github.com/atsamd-rs/atsamd/tree/master/boards/trellis_m4/examples

* Be in this directory `cd boards/trellis_m4`
* Put your device in bootloader mode usually by hitting the reset button twice.
* Build and upload in one step
```
$ cargo hf2 --release --example neopixel_rainbow
    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/trellis_m4/target/thumbv7em-none-eabihf/release/examples/neopixel_rainbow"
    Finished in 0.079s
$
```

## Optional `trellis_m4` Cargo Features

The following optional hardware drivers can be enabled as cargo features:

- `adxl343`: [ADXL343] accelerometer support
- `keypad-unproven`: (alpha) support for button input via the [keypad] crate

To enable them, use the `features` option when adding a crate dependency to
your Cargo.toml:

```toml
[dependencies]
trellis_m4 = { version = "~0.1", features = ["adxl343", "keypad-unproven"] }
```

Or when running an example:
```
$ cargo hf2 --release --example neopixel_keypad
error: target `neopixel_keypad` in package `trellis_m4` requires the features: `keypad-unproven`
Consider enabling them by passing, e.g., `--features="keypad-unproven"`
```
Just follow the instructions to add --features like
```
cargo hf2 --release --example neopixel_keypad --features="keypad-unproven"
    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("PyGamer"))
    Flashing "/Users/User/atsamd/boards/trellis_m4/target/thumbv7em-none-eabihf/release/examples/neopixel_keypad"
    Finished in 0.167s
$
```

## More Examples

[Adafruit NeoTrellis M4 board]: https://www.adafruit.com/product/3938
[ATSAMD51G]: https://www.microchip.com/wwwproducts/en/ATSAMD51G
[ADXL343]: https://www.analog.com/en/products/adxl343.html
[keypad]: https://crates.io/crates/keypad