Wireless

RMK has built-in wireless(BLE) support for nRF52840 and nRF52832. Supporting of other nRF52 microcontrollers should be quite easy to add. To use the wireless feature, enable nrf52832_ble or nrf52840_ble feature gate in your Cargo.toml:

rmk = { version = "0.1.12", features = [
    "nrf52840_ble",
    "col2row",
] }

RMK also provides ble examples, check nrf52840_ble and nrf52832_ble.

Due to multiple targets are not supported by docs.rs right now, so API documentations are not there. Check examples for the usage. I'll add a separate doc site later.

Flashing to your board

RMK can be flashed via a debug probe or USB. Follow the instruction in the examples/use_rust/nrf52840_ble/README.md

Nice!nano support

RMK has special support for nice!nano, a widely used board for building wireless keyboard.

nice!nano has a built-in bootloader, enables flashing a .uf2 format firmware via USB drive. examples/use_rust/nrf52840_ble/README.md provides instructions to convert RMK firmware to .uf2 format and flash to nice!nano.

There is another way to flash RMK firmware to nice!nano. It requires a modified version of elf2uf2-rs. The following are the steps:

1. Install elf2uf2-rs from https://github.com/simmsb/elf2uf2-rs:

   cargo install --git https://github.com/simmsb/elf2uf2-rs
   

2. Enter nice!nano's bootloader mode, a USB drive should appear in your machine
3. Check the softdevice version of your nice!nano. If it's v6.x.x, edit memory.x:

   - FLASH : ORIGIN = 0x00027000, LENGTH = 868K
   + FLASH : ORIGIN = 0x00026000, LENGTH = 872K
   

4. Update cargo runner in .cargo/config.toml, using elf2uf2-rs:

   [target.'cfg(all(target_arch = "arm", target_os = "none"))']
   - runner = "probe-rs run --chip nRF52840_xxAA"
   + runner = "elf2uf2-rs -d"
   

5. Flash using cargo run --release