30.5.3 Clocks

A generic clock (GCLK_SERCOMx_CORE) is required to clock the SERCOMx_CORE. This clock must be configured and enabled in the CRU registers before using the SERCOMx_CORE. See Clock and Reset (CRU) and Peripheral Module Disable Register (PMD) from Related Links.

This generic clock is asynchronous to the bus clock (PBx_CLK). Therefore, writing to certain registers will require synchronization to the clock domains.