A watchdog timer
is a safety
feature found in microprocessor
that prevents runaway software from halting a system which experiences a critical
system fault. When it times out, it stops a microprocessor from executing meaningless code
, a situation that arises from an electrical
or programming error
. More specifically, if the software
is not being executed properly, it fails to clear the watchdog timer; if the watchdog timer is not cleared for a specified interval
, the watchdog timer causes the microprocessor to reboot
and execute software from a designated location.
A watchdog timer is most useful for mission critical systems that must remain in continuous operation without human intervention, or in environments where personnel are not normally present or readily available to intervene should a system failure occur. This hardware-based feature is generally application-specific, and is often adequate safety in lieu of a redundant system.