WWDT - Windowed Watchdog Timer

A Watchdog Timer (WDT) is a system timer that generates a Reset if the firmware does not issue a CLRWDT instruction within the time-out period. A Watchdog Timer is typically used to recover the system from unexpected events. The Windowed Watchdog Timer (WWDT) differs from nonwindowed operation in that CLRWDT instructions are only accepted when they are performed within a specific window during the time-out period.

The WWDT has the following features:
Figure 1. Windowed Watchdog Timer Block Diagram