7

Pin Configuration

Pin Description

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

32KHZ

SCL

SDA

GND

N.C.

N.C.

N.C.

N.C.

TOP VIEW

SO

INT/SQW

N.C.

RST

N.C.

N.C.

N.C.

DS3231M

DS3231M

+

GND

RST

1

2

8

7

SCL

SDA

INT/SQW

32KHZ

SO

TOP VIEW

3

4

6

5

+

PIN

NAME

FUNCTION

8_SO

16_SO

1

1

32KHZ

32.768kHz Output (50% Duty Cycle). This open-drain pin requires an external pullup resistor.

When enabled with the EN32KHZ bit in the Status register (0Fh), this output operates on either

power supply. This pin can be left open circuit if not used.

2

2

DC Power Pin for Primary Power Supply. This pin should be decoupled using a 0.1FF to 1.0FF

capacitor. Connect to ground if not used.

3

3

INT/

SQW

Active-Low Interrupt or 1Hz Square-Wave Output. This open-drain pin requires an external pullup

resistor connected to a supply at 5.5V or less. It can be left open if not used. This multifunction

pin is determined by the state of the INTCN bit in the Control register (0Eh). When INTCN is set to

logic 0, this pin outputs a 1Hz square wave. When INTCN is set to logic 1, a match between the

timekeeping registers and either of the alarm registers activates the INT/SQW pin (if the alarm is

enabled). Because the INTCN bit is set to logic 1 when power is first applied, the pin defaults to

an interrupt output with alarms disabled.

4

4

RST

output is combined with a debounced pushbutton input function. This pin can be activated by a

RST immediately goes high.

—

5–12

N.C.

No Connection. These pins must be connected to ground.

5

13

GND

Ground

6

14

source, this pin should be decoupled using a 0.1FF to 1.0FF low-leakage capacitor. When using the

used, connect to ground. The device is UL recognized to ensure against reverse charging when