qmk_firmware/keyboards/nack/rules.mk

# MCU name
MCU = STM32F303
BOARD = QMK_PROTON_C

# Build Options
#   change yes to no to disable
#
BOOTMAGIC_ENABLE = no       # Virtual DIP switch configuration
MOUSEKEY_ENABLE = no        # Mouse keys
EXTRAKEY_ENABLE = no        # 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 = yes          # Audio output
RGB_MATRIX_ENABLE = yes
RGB_MATRIX_DRIVER = WS2812
WS2812_DRIVER = spi
AUDIO_DRIVER = dac_additive # How to drive the 2 speakers
UNICODE_ENABLE = yes        # Unicode support