Clock System Overview

The XMEGA Clock System provides a large portfolio of clock sources, both internal and external. In addition, an internal PLL can be used to multiply selected clock sources with a factor ranging from 1x to 31x.

In order to ease implementations, the default clock setting for the XMEGA is to start up running from an internal 2MHz factory-calibrated source. In this way, if the default settings are sufficient, no external components or software configuration is required to start executing code.

The following sections describe the various clock sources and the available configuration options for using one of them as a main system clock.