The DS1284 Watchdog Timekeeper Chip is a self-contained real-time clock, alarm, watchdog timer, and interval timer in a 28-pin JEDEC DIP package or a 28-pin PLCC surface mount package. An external crystal and battery are the only components required to maintain time-of-day and memory status in the absence of power. For a complete description of operating conditions, electrical characteristics, bus timing, and pin descriptions other than X1, X2, VBAT, and RCLR , see the DS1286 Watchdog Timekeeper data sheet.