Rainbow Electronics DS1202S User Manual
Rainbow Electronics Computer hardware
DS1202, DS1202S
Serial Timekeeping Chip
DS1202, DS1202S
E
Copyright 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
•
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 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
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
V
CC
NC
SCLK
NC
I/O
NC
NC
RST
16–PIN SOIC
8–PIN DIP
V
CC
SCLK
I/O
RST
NC
X1
X2
GND
1
2
3
4
8
7
6
5
V
CC
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
V
CC
– 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.