33.6.1 WDT Operation in Power-Saving Modes

The WDT, if enabled, will continue operation in Sleep mode or Idle mode and can be used to wake the device. This allows the device to remain in Sleep or Idle mode until the WDT expires or another interrupt wakes the device. If the device does not re-enter Sleep or Idle mode following a wake-up, the WDT must be disabled or periodically serviced to prevent a WDT Run mode NMI.