qmk_firmware/keyboards/crkbd/rules.mk

# MCU name
MCU = atmega32u4

# Bootloader selection
BOOTLOADER = caterina

# Build Options
#   change yes to no to disable
#
BOOTMAGIC_ENABLE = lite     # Enable Bootmagic Lite
MOUSEKEY_ENABLE = yes       # Mouse keys
EXTRAKEY_ENABLE = yes       # Audio control and System control
CONSOLE_ENABLE = no         # Console for debug
COMMAND_ENABLE = no         # Commands for debug and configuration
# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
NKRO_ENABLE = yes           # USB Nkey Rollover
BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
BLUETOOTH_ENABLE = no       # Enable Bluetooth
AUDIO_ENABLE = no           # Audio output
RGB_MATRIX_ENABLE = no
RGB_MATRIX_DRIVER = WS2812

# if firmware size over limit, try this option
# LTO_ENABLE = yes

DEFAULT_FOLDER = crkbd/rev1

RGBLIGHT_SUPPORTED = yes
RGB_MATRIX_SUPPORTED = yes

LAYOUTS = split_3x5_3 split_3x6_3