DS1202, DS1202S
DS1202, DS1202S
Serial Timekeeping Chip
FEATURES
PIN ASSIGNMENT
NC
X1
X2
GND
1
2
3
4
8
7
6
5
V
CC
SCLK
I/O
RST
•
Real time clock counts seconds, minutes, hours, date
of the month, month, day of the week, and year with
leap year compensation valid up to 2100
•
24 x 8 RAM for scratchpad data storage
•
Serial I/O for minimum pin count
•
2.0–5.5 volt full operation
•
Uses less than 300 nA at 2 volts
•
Single–byte or multiple–byte (burst mode) data trans-
fer for read or write of clock or RAM data
8–PIN DIP
NC
X1
X2
GND
1
2
3
4
8
7
6
5
V
CC
SCLK
I/O
RST
8–PIN SOIC
(208 mil)
NC
NC
X1
NC
X2
NC
NC
1
2
3
4
5
6
7
8
16–PIN SOIC
16
15
14
13
12
11
10
9
V
CC
NC
SCLK
NC
I/O
NC
NC
RST
•
8–pin DIP or optional 16–pin SOIC for surface mount
•
Simple 3–wire interface
•
TTL–compatible (V
CC
= 5V)
•
Optional industrial temperature range –40°C to +85°C
(IND)
ORDERING INFORMATION
DS1202
DS1202S
DS1202S–8
DS1202N
DS1202SN
DS1202SN–8
8–pin DIP
16–pin SOIC
8–pin SOIC
8–pin DIP (IND)
16–pin SOIC (IND)
8–pin SOIC (IND)
GND
PIN DESCRIPTION
NC
X1, X2
GND
RST
I/O
SCLK
V
CC
–
–
–
–
–
–
–
No Connection
32.768 KHz Crystal Input
Ground
Reset
Data Input/Output
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.
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
DALLAS [ DALLAS SEMICONDUCTOR ]
