qmk_firmware/keyboards/ymdk/sp64/rules.mk

# MCU name
MCU = atmega32a

# Bootloader selection
BOOTLOADER = bootloadhid

# Build Options
#   change yes to no to disable
#
BOOTMAGIC_ENABLE = yes      # Enable Bootmagic Lite
MOUSEKEY_ENABLE = no        # Mouse keys
EXTRAKEY_ENABLE = yes       # Audio control and System control
CONSOLE_ENABLE = no         # Console for debug
COMMAND_ENABLE = yes        # Commands for debug and configuration
NKRO_ENABLE = no            # Enable N-Key Rollover
BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
AUDIO_ENABLE = no           # Audio output
AUDIO_SUPPORTED = no
RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
CUSTOM_MATRIX = yes

# Needed for underglow
WS2812_DRIVER = i2c

SRC += matrix.c
QUANTUM_LIB_SRC += i2c_master.c