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 non-windowed 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:
- Selectable clock source
- Multiple operating modes
- WWDT is always on
- WWDT is off when in Sleep
- WWDT is controlled by software
- WWDT is always off
- Configurable time-out period from 1 ms to 256s (nominal)
- Configurable window size from 12.5% to 100% of the time-out period
- Multiple Reset conditions
Figure 1. Windowed Watchdog Timer Block
Diagram
