DS12887A Datasheet PDF - Dallas Semiconductor

●DESCRIPTION

●The DS1287A is identical to the DS1287 with the addition of the RAM clear pin. For a complete description of

●operating conditions, electrical and mechanical characteristics, bus timing, and pin descriptions see the DS12887A data sheet.

●FEATURES

●•Drop-in replacement for IBM AT computer clock/calendar

●•Pin compatible with the MC146818A

●•Totally nonvolatile with over 10 years of operation in the absence of power

●•Self-contained subsystem includes lithium, quartz, and support circuitry

●•Counts seconds, minutes, hours, day of the week, date, month, and year with leap year compensation

●•Binary or BCD representation of time, calendar, and alarm

●•12- or 24-hour clock with AM and PM in 12-hour mode

●•Daylight Savings Time option

●•Selectable between Motorola and Intel bus timing

●•Multiplex bus for pin efficiency

●•Interfaced with software as 64 RAM locations

●– 14 bytes of clock and control registers

●– 50 bytes of general purpose RAM

●•Programmable square wave output signal

●•Bus-compatible interrupt signals (IRQ)

●•Three interrupts are separately software-maskable and testable

●– Time-of-day alarm once/second to once/day

●– Periodic rates from 122 sto 500 ms

●– End of clock update cycle