These devices combine two popular functions, Watchdog Timer, and Serial E2PROM Memory in one package. This combination lowers system cost, reduces board space requirements, and increases reliability. The Watchdog Timer provides an independent protection mechanism for microcontrollers. During a system failure, the device will respond with a RESET/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 memory portion of the device is a CMOS Serial E2PROM array with Xicor's Block LockTM Protection. The array is internally organized as x 8. The device features a Serial Peripheral Interface (SPI) and software protocol allowing operation on a simple four-wire bus. The device utilizes Xicor's proprietary Direct WriteTM cell, providing a minimum endurance of 100,000 cycles per sector and a minimum data retention of 100 years.