14 WDT - Watchdog Timer

The Watchdog Timer (WDT) is a system timer that generates a Reset event if the firmware does not issue a CLRWDT instruction within the time-out period. The Watchdog Timer is typically used to reset the processor in the event of a software malfunction, but can also be used to wake the device when in Sleep mode.

The WDT has the following features:

  • Selectable clock sources
  • Multiple operating modes:
    • WDT is always on
    • WDT is off when in Sleep
    • WDT is controlled by software
    • WDT is always off
  • Configurable time-out period from 1 ms to 256 seconds (nominal)
  • Multiple Reset conditions
  • Operation during Sleep
Figure 14-1. Watchdog Timer (WDT) Block Diagram