Depending on the application, peripherals may require specific
clock frequencies to operate correctly. The Generic Clock controller (GCLK) features 5 Generic Clock Generators 0..4 that can provide a wide range of clock
frequencies.
Generators can be set to use different external and
internal oscillators as source. The clock of each Generator can be divided. The outputs
from the Generators are used as sources for the Peripheral Channels, which provide the
Generic Clock (GCLK_PERIPH) to the peripheral modules, as shown in
Figure 2. The number of Peripheral Clocks depends on how many
peripherals the device has.
Note: The
Generator 0 is always the direct source of the GCLK_MAIN signal.