RPK - Rust Programmable Keyboard

RPK is a keyboard firmware builder written in rust for hobbyist mechanical keyboards. It is modeled on the excellent configuration of keyd. Check out the User Guide for information about building firmware for your keyboard.

Features

• Text file configuration which can be uploaded instantly via the rpk-config companion program (no need to re-flash firmware).
• 256 low cost layers.
• Arbitrarily many macros.
• Sensible key overloading, oneshot layers and changeable base layout.
• Modifiers are layers.
• Mouse support with changeable acceleration profiles.
• n-key rollover, consumer and sys ctl keycode support.
• Unicode support.
• Ring file system for storing multiple configurations.
• Clear, reset, bootloader actions and reset on panic.
• Low latency debounce logic.
• Low overhead firmware - uses rust embassy async embedded framework.

Example config file

Example is for a 3x3 macropad with a Raspberry Pi Pico (rp2040) micro controller.

[firmware]

# USB interface
# =============
vendor_id           = 0xceeb # 4 hex-digit number; try to be unique.
product_id          = 0xb0ad # 4 hex-digit number; try to be unique per vendor_id.
serial_number       = rpk:1234 # must start with rpk: unique per product, vendor_id.
manufacturer        = Jacott
product             = RPK macropad
max_power           = 100 # 0 to 500 (mA). Default 100

# Chipset and pin assignments
# ===========================
chip                = rp2040
# Pin names are from the chipset crate. For rp2040 it is the embassy_rp crate
output_pins         = [PIN_4, PIN_5, PIN_6]
input_pins          = [PIN_7, PIN_8, PIN_9]
row_is_output       = true # the output pins are connected to the keyboard rows

# Memory allocation
# =================

# Flash ring file system used to hold layouts, security tokens, dynamic macros...
flash_size          = 2 * 1024 * 1024 # 2MB matches memory.x file
fs_base             = 0x100000 # room for other things like firmware
# ensure fs_size is multiple of flash erase size (4K)
fs_size             = flash_size - fs_base

# How much room to reserve for layout configuration + runtime requirements.
max_layout_size     = 8 * 1024

# How many messages can we queue to the usb interface without waiting.
report_buffer_size  = 32

# How many key events can we scan without waiting.
scanner_buffer_size = 32

[matrix:3x3]
# I/O pin mapping to key codes
# ============================
# Names for row,column and default main layer key code. Codes can be pseudo code like u1
# or k24 which will map to noop by default.

# 0x00 means start assigning from row 0, column 0. 0x5a would mean start from row 5,
# column 10. If there are more than 16 rows or columns you can use 4 hex digits like,
# say 0x1234 for row 18, column 52. A maximum of 127 rows and columns is allowed.

0x00                = 7 8 9
0x10                = 4 5 6
0x20                = 1 2 3

# Customized layers/layout
# ========================

[main] # main layout. Overrides the keycodes given in matrix section.

3                   = overload(mouse, 3) # mouse layer on hold, 3 on tap
1                   = overload(shift, 1) # shift layer on hold, 1 on tap

[mouse] # layers can have any name.

8                   =           mouseup
4                   = mouseleft mousedown mouseright
1                   = mouse1    mouse2

[shift] # control, shift, alt and meta (a.k.a super) correspond to the modifier keys

3                   = macro(hello space world) # taps out "hello world"

Planned future features

• Web and binary Graphical configuration app.
• Host daemon app for displaying keyboard information and changing keyboard layers/configuration based on host application in focus.
• Composite layers.
• Tap dance.
• record/play macros and store in flash.
• Key chording.
• LED support.
• Bluetooth/RF/Wifi support.
• Multi mcu/split keyboard support.
• Macro support/Test on other mcus (other than rp2040).
• Templates for other mcus.
• Security features to protect uploading.
• Macros to load other keyboard mapping stored on keyboard.
• Hot load new firmware - (not needed for rp2040).

License

MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)