Windowed Watchdog Enhances µP Supervisors

Abstract: Watchdog timers increases reliability in microprocessor-based systems. Pin-selectable watchdog timers allow the watchdog time-out period to be adjustable, thus allowing more flexibility to meet different processor timing requirements. Windowed watchdog circuits provide protection against systems from running too fast and too slow. A separate open-drain, active-low, output is used to signal a watchdog time-out.

In many of these circuits, additional features are included for more functionality. Such features include a voltage-reset circuit with either a push-pull or open-drain reset output. In some circuits, a manual reset input is included.