33.6.2 WDT Operation in Sleep Mode
The WDT module may be used to wake the device from Sleep mode. When entering Sleep mode, the WDT Run mode counter stops counting and the Power Save mode WDT begins counting from the Reset state until it times out or the device is woken up by an interrupt. When the WDT times out in Sleep mode, the device wakes up, resumes code execution and resumes the Run mode WDT.