DS1688/DS1691

3 of 6

PIN DESCRIPTION

PIN

SO

EDIP

NAME

FUNCTION

1

1

Auxiliary Battery Supply

2, 3

—

X1, X2

Crystal Input, Crystal Output

4

4

RCLR

Active-Low RAM Clear Input

5–12

5–12

AD0–AD7

Muxed Address/Data Bus

13

13

PWR

Active-Low Power-On Interrupt Output

14, 19

14

GND

Ground

15

15

KS

Active-Low Kickstart Input

16

16

CS

Active-Low Chip Select Input

17

17

ALE

Address Strobe

18

18

WR

Active-Low Write Data Strobe

20

20

RD

Active-Low Read Data Strobe

21

21

PSEL

+3V or +5V Power Select

22

22

IRQ

Active-Low Interrupt Request Output

23

—

Battery + Supply

24

24

SQW

Square-Wave Output. This signal functions identical to the

DS1689/DS1693 with an exception occurring at power-up. A

condition has been detected. This condition sets the following

bits, enabling the 32kHz output: DV1 = 1, SQWE = 1, and E32K

= 1. The square wave is output on this pin if either SQWE = 1 or

E32K = 1.

25

25

RAM Power-Supply Output

26

26

+3V or +5V Main Supply

27

27

CEO

Active-Low RAM Chip Enable Out

28

28

CEI

Active-Low RAM Chip Enable In

—

2, 3, 19,

23

N.C.

No Connection