DS1284/DS1286

3 of 18

PIN DESCRIPTION

PIN

DIP

EDIP

PLCC

NAME

FUNCTION

1

1

1

INTA

Active-Low Interrupt Output A. This open-drain pin requires a

pullup resistor for proper operation.

2, 3

—

2, 3

X1, X2

Connections for Standard 32.768kHz Quartz Crystal. The internal

oscillator circuitry is designed for operation with a crystal having

directly to the X1 and X2 pins. There is no need for external

capacitors or resistors. For more information on crystal selection

and crystal layout considerations, refer to Application Note 58:

Crystal Considerations with Dallas Real Time Clocks.

4

2, 3, 4,

21, 24,

25

4

N.C.

No Connection

5–10

5–10

5–10

A5–A0

Address Inputs

11, 12,

13, 15,

16–19

11, 12,

13, 15,

16–19

11, 12,

13, 15,

16–19

DQ0, DQ1,

DQ2, DQ3,

DQ4–DQ7

Data Input/Output

14, 21

14

14, 21

GND

Ground

20

20

20

CE

Active-Low Chip-Enable Input

22

22

22

OE

Active-Low Output-Enable Input

23

23

23

SQW

Square-Wave Output. Push-pull output. High impedance when

24

—

24

RCLR

Active-Low RAM Clear. Used to clear (set to logic 1) all 50

bytes of user NV RAM, but does not affect the registers

involved with time, alarm, and watchdog functions. To clear the

RAM,

RCLR must be forced to an input logic 0 (-0.3V to

The

RCLR function is designed to be used via human interface

(shorting to ground or by switch) and not be driven with external

buffers. This pin is internally pulled up and should be left

floating when not in use.

25

—

25

Input for Any Standard 3V Lithium Cell or Other Energy

Source. Input voltage must be held between the minimum and

maximum limits for proper operation. The supply should be

not necessary because reverse charging current-protection

circuitry is provided internal to the device and has passed the

requirements of Underwriters Laboratories for UL listing. This

pin should be grounded but can be left floating.

26

26

26

INTB

(INTB)

Active-Low (Active-High) Interrupt Output B. When the active-

high state is selected (IBH = 1), an open-drain pullup transistor

When the active-low state is selected (IBH = 0), an open-drain

pulldown transistor connected to ground sinks current when the

output is active. If active-high output operation is selected, a

pulldown resistor is required for proper operation. When active-

low output operation is selected, a pullup resistor is required for

proper operation.

27

27

27

WE

Active-Low Write-Enable Input