Use keyboard.toml

The generated main.rs should be like:

#![allow(unused)]
fn main() {
use rmk::macros::rmk_keyboard;
use vial::{VIAL_KEYBOARD_DEF, VIAL_KEYBOARD_ID};

#[rmk_keyboard]
mod keyboard {}
}

There's a macro rmk_keyboard that does the magic for you. This macro will automatically read the keyboard.toml in your project root and generate all boilerplate code for you.

There're steps you have to do to customize your own firmware:

Edit keyboard.toml

The generated keyboard.toml should have some fields configured from cargo generate. But there are still some fields that you want to fill, such as the pin matrix, default keymap, led config, etc.

The Keyboard Configuration section has full instructions of how to write your own keyboard.toml. Follow the doc and report any issues/questions at https://github.com/HaoboGu/rmk/issues. We appreciate your feedback!

Update memory.x

memory.x is the linker script of Rust embedded project, it's used to define the memory layout of the microcontroller. RMK enables memory-x feature for embassy-stm32, so if you're using stm32, you can just ignore this step.

For other ARM Cortex-M microcontrollers, you only need to update the LENGTH of FLASH and RAM to your microcontroller.

If you're using nRF52840, generally you have to change start address in memory.x to 0x27000 or 0x26000, according to your softdevice version. For example, softdevice v6.1.x should use 0x00026000 and v7.3.0 should be 0x00027000

You can either checkout your microcontroller's datasheet or existing Rust project of your microcontroller for it.

Add your own layout

The layout should be consistent with the default keymap set in keyboard.toml

The next step is to add your own keymap layout for your firmware. RMK supports vial app, an open-source cross-platform(windows/macos/linux/web) keyboard configurator. So the vial like keymap definition has to be imported to the firmware project.

Fortunately, RMK does most of the heavy things for you, all you need to do is to create your own keymap definition and convert it to vial.json following vial's doc here, and place it at the root of the firmware project, replacing the default one. RMK would do all the rest things for you.