29.6.2.1 Initialization

The SERCOM bus clock (CLK_SERCOMx_APB) is required to access the SERCOM registers. This clock must be enabled in the MCLK - Main Clock Controller.

Two generic clocks are used by the SERCOM: GCLK_SERCOMx_CORE is required to clock the SERCOM while working as a Host, and GCLK_SERCOM_SLOW is required only for certain functions. See specific mode chapters for details. These clocks must be configured and enabled in the GCLK - Generic Clock Controller before using the SERCOM.

The SERCOM must be configured to the desired mode by writing the Operating Mode bits in the Control A register (CTRLA.MODE). Refer to the following table for details.

For further initialization information, see the respective SERCOM mode chapters:

• SERCOM SPI
• SERCOM USART
• SERCOM I²C