DS1287A Datasheet | Dallas Semiconductor

FEATURES .. PIN ASSIGNMENT MOT NC NC AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 GND 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 VCC SQW NC RCLR NC IRQ RESET DS NC R/W AS CS - Drop-in replacement for IBM AT puter clock/calendar - Pin patible with the MC146818A - Totally nonvolatile with over 10 years of operation in the absence of power - Self-contained - Counts subsystem includes lithium, quartz, and support circuitry seconds, minutes, hours, day of the week, date, month, and year with leap year pensation alarm - Binary or BCD representation of time, calendar, and - 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 24 PIN ENCAPSULATED PACKAGE PIN DESCRIPTION AD0- AD7 NC MOT CS AS R/W DS RESET IRQ drain) SQW VCC GND RCLR Multiplexed address/data bus No connection Bus type selection Chip select Address strobe Read/write input Data strobe Reset input Interrupt request output (open Square wave output +5 volt supply Ground RAM clear - Programmable square wave output signal - Bus-patible interrupt signals (IRQ) - Three interrupts are separately software-maskable and testable - Time-of-day alarm once/second to once/day - Periodic rates from 122 ms to 500 ms - End of clock update cycle DESCRIPTION The DS1287A is identical to the DS1287 with the addition of the RAM clear pin. For a plete description of operating conditions, electrical and mechanical characteristics, bus timing, and pin descriptions see the DS12887A data sheet. 022798...