DS1202, DS1202S

Serial Timekeeping Chip

DS1202, DS1202S

ECopyright 1997 by Dallas Semiconductor Corporation.

All Rights Reserved. For important information regarding

patents and other intellectual property rights, please refer to

Dallas Semiconductor data books.

032697 1/11

FEATURES

of the month, month, day of the week, and year with

leap year compensation valid up to 2100

fer for read or write of clock or RAM data

(IND)

ORDERING INFORMATION

DS1202

8–pin DIP

DS1202S

16–pin SOIC

DS1202S–8

8–pin SOIC

DS1202N

8–pin DIP (IND)

DS1202SN

16–pin SOIC (IND)

DS1202SN–8 8–pin SOIC (IND)

PIN ASSIGNMENT

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

NC

NC

X1

NC

X2

NC

NC

GND

NC

SCLK

NC

I/O

NC

NC

RST

16–PIN SOIC

8–PIN DIP

SCLK

I/O

RST

NC

X1

X2

GND

1

2

3

4

8

7

6

5

SCLK

I/O

RST

NC

X1

X2

GND

1

2

3

4

8

7

6

5

8–PIN SOIC

(208 mil)

PIN DESCRIPTION

NC

– No Connection

X1, X2

– 32.768 KHz Crystal Input

GND

– Ground

RST

– Reset

I/O

– Data Input/Output

SCLK

– Serial Clock

– Power Supply Pin

DESCRIPTION

The DS1202 Serial Timekeeping Chip contains a real

time clock/calendar and 24 bytes of static RAM. It com-

municates with a microprocessor via a simple serial in-

terface. The real time clock/calendar provides seconds,

minutes, hours, day, date, month, and year information.

The end of the month date is automatically adjusted for

months with less than 31 days, including corrections for

leap year. The clock operates in either the 24–hour or

12–hour format with an AM/PM indicator. Interfacing the

DS1202 with a microprocessor is simplified by using

synchronous serial communication. Only three wires

are required to communicate with the clock/RAM: (1)

RST (Reset), (2) I/O (Data line), and (3) SCLK (Serial

clock). Data can be transferred to and from the clock/

RAM one byte at a time or in a burst of up to 24 bytes.

The DS1202 is designed to operate on very low power

and retain data and clock information on less than 1 mi-

crowatt.