The bq3287 is a fully compatible r e a l - t i m e c l o c k f o r I B M ATcompatible computers and other app l i c a t i o n s. T h e b q 3 2 8 7 w r i t e protects the clock, calendar, and storage registers during power failure. The integral backup energy source then maintains data and operates the clock and calendar. As shipped from Benchmarq, the real time clock is turned off to maximize battery capacity for in-system operation.