This application note describes PSoC 3 and PSoC 5LP's oscillators and clock sources, phase-locked loop (PLL), and clock distribution network. However, it does not cover the details of the external crystal oscillators (ECOs). For those details, see AN54439 - PSoC® 3 and PSoC 5LP External Crystal Oscillator.
Clocks play a critical part in microcontroller operation. They are used to synchronize internal signals, ensure error free communication with other digital devices, and drive the conversion of signals to and from the analog domain. These roles make the configuration of the different clocks used inside of a microcontroller very important.
