In this use case, the GCLK module is configured for:
One generator attached to the internal 8MHz RC oscillator clock source
Generator output equal to input frequency divided by a factor of 128
One channel (connected to the TC0 module) enabled with the enabled generator selected
This use case configures a clock channel to output a clock for a peripheral within the device, by first setting up a clock generator from a master clock source, and then linking the generator to the desired channel. This clock can then be used to clock a module within the device.