13.5.6.1 Principle of Operation
The GCLK module is comprised of nine Generic Clock Generators (Generators) sourcing up to 64 Peripheral Channels and the Main Clock signal GCLK_MAIN.
A clock source selected as input to a Generator can either be used directly, or it can be prescaled in the Generator. A generator output is used by one or more Peripheral Channels to provide a peripheral generic clock signal (GCLK_PERIPH) to the peripherals.