DS1285 Datasheet | Dallas Semiconductor

FEATURES .. PIN ASSIGNMENT MOT X1 X2 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 VBAT IRQ RESET DS GND R/W AS CS - Drop-in replacement for IBM AT puter clock/calendar - Pin configuration closely matches MC146818A - Counts 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 DS1285 24- PIN DIP VCC SQW MOT NC NC X2 4 AD0 AD1 AD2 AD3 AD4 AD5 NC 5 6 7 8 9 10 X1 3 2 1 28 27 26 25 24 23 22 21 20 RCLR VBAT IRQ RESET DS GND R/W - 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 µs to 500 ms - End of clock update cycle 19 11 12 13 14 15 16 17 18 AD6 AD7 GND NC NC CS AS DS1285Q 28-PIN PLCC - Optional 28-pin PLCC surface mount package DESCRIPTION The DS1285 Real Time Chip is a direct replacement for the MC146818A in IBM AT puter clock/calendar and other applications. For a plete description of operating conditions, electrical and mechanical characteristics, bus timing, and pin descriptions see the DS12885 data sheet. PIN DESCRIPTION AD0-AD7 NC MOT CS AS R/W DS RESET IRQ SQW VCC GND X1,X2 VBAT RCLR - - - - - - - - - - - -...