32.6.5 Sleep Mode Operation

The behavior in Sleep mode is depending 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 (except Frame error (FERR) and Parity error (PERR) that are part of the ERROR interrupt).
  • External clocking, CTRLA.RUNSTDBY = 1: The Receive Complete interrupt(s) can wake-up the device
  • Internal clocking, CTRLA.RUNSTDBY = 0: Internal clock will be disabled, after any ongoing transfer was completed. The Receive Complete interrupt(s) can wake-up the device.
  • External clocking, CTRLA.RUNSTDBY = 0: External clock will be disconnected, after any ongoing transfer was completed. All reception will be dropped.

When targeting the lowest STANDBY power consumption for a transmit only application, the Receiver must remain disabled, but the receiver data pinout (CTRLA.RXPO) must be set to match the transmit data pinout (CTRLA.TXPO).