qmk_firmware/keyboards/mt40/rules.mk

# MCU name
MCU = atmega32a
PROTOCOL = VUSB

# unsupported features for now
NO_UART = yes
NO_SUSPEND_POWER_DOWN = yes

# processor frequency
F_CPU = 12000000

# Bootloader
#     This definition is optional, and if your keyboard supports multiple bootloaders of
#     different sizes, comment this out, and the correct address will be loaded 
#     automatically (+60). See bootloader.mk for all options.
BOOTLOADER = bootloadHID

# build options
BOOTMAGIC_ENABLE ?= yes # Virtual DIP switch configuration(+1000)
MOUSEKEY_ENABLE ?= no   # Mouse keys(+4700)
EXTRAKEY_ENABLE ?= yes  # Audio control and System control(+450)
CONSOLE_ENABLE ?= no    # Console for debug(+400)
COMMAND_ENABLE ?= no    # Commands for debug and configuration
NKRO_ENABLE ?= no       # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ # nkro-doesnt-work
BACKLIGHT_ENABLE ?= yes # Enable keyboard backlight functionality
MIDI_ENABLE ?= no       # MIDI controls
AUDIO_ENABLE ?= no      # Audio output on port C6
UNICODE_ENABLE ?= no    # Unicode
BLUETOOTH_ENABLE ?= no  # Enable Bluetooth with the Adafruit EZ-Key HID
RGBLIGHT_ENABLE ?= yes  # Enable WS2812 RGB underlight.  Do not enable this with audio at the same time.
RGBLIGHT_CUSTOM_DRIVER = yes
TAP_DANCE_ENABLE = no

OPT_DEFS = -DDEBUG_LEVEL=0

# custom matrix setup
CUSTOM_MATRIX = yes
SRC = matrix.c i2c.c

# programming options
PROGRAM_CMD = ./util/atmega32a_program.py $(TARGET).hex