| Drop-in replacement for IBM AT computer clock/calendarPin compatible with the MC146818B and DS1287ATotally nonvolatile with over 10 years of operation in the absence of powerSelf-contained subsystem includes lithium, quartz, and support circuitryCounts seconds, minutes, hours, days, day of the week, date, month, and year with leap year compensation valid up to 2100Binary or BCD representation of time, calendar, and alarm12- or 24-hour clock with AM and PM in 12-hour modeDaylight Savings Time optionSelectable between Motorola and Intel bus timingMultiplex bus for pin efficiencyInterfaced with software as 128 RAM locations 14 bytes of clock and control registers 114 bytes of general purpose RAM Programmable square-wave output signalBus-compatible interrupt signals (IRQ)Three interrupts are separately software-maskable and testable Time-of-day alarm once/second to once/day Periodic rates from 122ms to 500ms End of clock update cycleUnderwriters Laboratory (UL) recognized |