30.6.2.1 Initialization
The SERCOM must be configured to the desired mode by writing the Operating Mode bits in the Control A register (CTRLA.MODE) as shown in the table below.
| CTRLA.MODE | Description | 
|---|---|
| 0x0 | USART with external clock | 
| 0x1 | USART with internal clock | 
| 0x2 | SPI in client operation | 
| 0x3 | SPI in host operation | 
| 0x4 | I2C client operation | 
| 0x5 | I2C host operation | 
| 0x6-0x7 | Reserved | 
For further initialization information, see the respective SERCOM mode chapters:
