32.6.5 Sleep Mode Operation

The behavior in Sleep mode is dependent on the clock source and the Run In Standby bit in the Control A register (CTRLA.RUNSTDBY):

• Internal clocking, CTRLA.RUNSTDBY = 1 – GCLK_SERCOMx_CORE can be enabled in all sleep modes. Any interrupt can wake up the device.
• External clocking, CTRLA.RUNSTDBY = 1 – The Receive Complete interrupt(s) can wake up the device.
• Internal clocking, CTRLA.RUNSTDBY = 0 – The internal clock is disabled, after any ongoing transfer is complete. The Receive Complete interrupt(s) can wake up the device.
• External clocking, CTRLA.RUNSTDBY = 0 – The external clock is disconnected, after any ongoing transfer is complete. All reception is dropped.