# If no clock division is performed on the input clock inside the AVR (via the
# CPU clock adjust registers or the clock division fuses), this will be equal to F_CPU.
F_USB ?= $(F_CPU)
# If no clock division is performed on the input clock inside the AVR (via the
# CPU clock adjust registers or the clock division fuses), this will be equal to F_CPU.
F_USB ?= $(F_CPU)