31.5.3 Clocks

The SERCOM bus clock (CLK_SERCOMx_APB) can be enabled and disabled in the main clock, and the default state of CLK_SERCOMx_APB can be found in the Peripheral Clock Masking section in the MCLK – Main Clock chapter.

The SERCOM uses two generic clocks: The Core clock (GCLK_SERCOMx_CORE) and the Slow clock (GCLK_SERCOMx_SLOW). The Core clock is required for SERCOM operation as a host, while the Slow clock is only needed for certain functions. See specific mode chapters for details.

These clocks must be configured and enabled in the generic clock controller before using the SERCOM. Refer to the GCLK – Generic Clock Controller chapter for details.

The generic clocks are asynchronous to the user interface clock (CLK_SERCOMx_APB). Due to this asynchronicity, writes to certain registers will require synchronization between the clock domains.