24.6.6 Sleep Mode Operation
The WDT will continue to operate in any sleep mode where the source clock is active except backup mode. The WDT interrupts can be used to wake up the device from a sleep mode. An interrupt request will be generated after the wake-up if the Interrupt Controller is configured accordingly. Otherwise the CPU will wake up directly, without triggering an interrupt. In this case, the CPU will continue executing from the instruction following the entry into sleep.
References: