DS1746/DS1746P

2 of 18

PIN DESCRIPTION

A0–A16

– Address Input

CE

– Chip Enable

OE

– Output Enable

WE

– Write Enable

– Power Supply Input

GND

– Ground

DQ0–DQ7

– Data Input/Output

NC

– No Connection

RST

– Power–on Reset Output (Power–

Cap Module board only)

X1, X2

– Crystal Connection

– Battery Connection

ORDERING INFORMATION

DS1746P

(5V)

blank

32-pin DIP Module

P

34-pin PowerCap Module board*

DS1746WP

(3.3V)

blank 32-pin DIP Module

P

34-pin PowerCap Module board*

*DS9034PCX (PowerCap) Required:

(must be ordered separately)

DESCRIPTION

The DS1746 is a full function, year 2000 compliant (Y2KC), real-time clock/calendar (RTC) and 128k x

8 non-volatile static RAM. User access to all registers within the DS1746 is accomplished with a

bytewide interface as shown in Figure 1. The Real Time Clock (RTC) information and control bits reside

in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours,

minutes, and seconds data in 24-hour BCD format. Corrections for the date of each month and leap year

are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data

that can occur during clock update cycles. The double buffered system also prevents time loss as the

timekeeping countdown continues unabated by access to time register data. The DS1746 also contains its

as errant access and update cycles are avoided.