qmk_firmware/keyboards/lfkeyboards/smk65/rules.mk

MCU = at90usb646
OPT_DEFS += -DBOOTLOADER_SIZE=4096

# Extra source files for IS3731 lighting
SRC = TWIlib.c issi.c lighting.c

# Processor frequency.
F_CPU = 16000000

# Target architecture (see library "Board Types" documentation).
ARCH = AVR8

# Input clock frequency.
F_USB = $(F_CPU)

# Interrupt driven control endpoint task(+60)
OPT_DEFS += -DINTERRUPT_CONTROL_ENDPOINT