The DS12C887A real-time clock plus RAM is designed to be a direct upgrade replacement for the DS12887A in existing IBM-compatible personal computers to add hardware year-2000 compliance. A century byte was added to memory location 50, 32h, as called out by the PC AT specification. The DS12C887A is identical in form, fit, and function to the DS1287A, and provides additional 64 bytes of general-purpose RAM. Access to this additional RAM space is determined by the logic level presented on AD6 during the address portion of an access cycle. The RCLR pin is used to clear (set to logic 1) all 113 bytes of general purpose RAM but does not affect the RAM associated with the real time clock. In order 1 of 2