The watchdog timer provides an independent protection mechanism for microcontrollers. During a system failure, the device will respond with a RESET signal after a selectable time out interval. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power. The user's system is protected from low voltage conditions by the device's low VCC detection circuitry. When VCC falls below the minimum VCC trip point, the system is reset. RESET is asserted until VCC returns to proper operating levels and stabilizes. Five industry standard VTRIP thresholds are available, however, Intersil's unique circuits allow the threshold to be reprogrammed to meet custom requirements or to fine-tune the threshold for applications requiring higher precision. The device utilizes Intersil's proprietary Direct WriteTM cell for the watchdog timer control bits and the VTRIP storage element, providing a minimum endurance of 100,000 write cycles and a minimum data retention of 100 years.