33.6.2.2 Enabling, Disabling, and Resetting
This peripheral is enabled by writing '1' to the Enable bit in the Control A register (CTRLA.ENABLE), and disabled by writing '0' to it.
Writing ‘1’ to the Software Reset bit in the Control A register (CTRLA.SWRST) will reset all registers of this peripheral to their initial states, except the DBGCTRL register, and the peripheral is disabled.
Note: Software Reset (CTRLA.SWRST=1) is not functional when the SERCOM is not enabled
(CTRLA.ENABLE=0).
Refer to the CTRLA register description for details.