I2C RTC
DS1340
I2C RTC with Trickle Charger
General Description
The DS1340 is a real-time clock (RTC)/calendar that is pin com...
Description
DS1340
I2C RTC with Trickle Charger
General Description
The DS1340 is a real-time clock (RTC)/calendar that is pin compatible and functionally equivalent to the ST M41T00, including the software clock calibration. The device additionally provides trickle-charge capability on the VBACKUP pin, a lower timekeeping voltage, and an oscillator STOP flag. Block access of the register map is identical to the ST device. Two additional registers, which are accessed individually, are required for the trickle charger and flag. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. A built-in power-sense circuit detects power failures and automatically switches to the backup supply. Reads and writes are inhibited while the clock continues to run. The device is programmed serially through an I2C bidirectional bus.
Applications
Portable Instruments
Point-of-Sale Equipment
Medical Equipment
Telecommunications
Typical Operating Circuit
VCC VCC
CRYSTAL
VCC RPU
RPU
1
28
X1 6 SCL
X2
VCC 7
FT/OUT
CPU DS1340
5 SDA RPU = tR / CB
3 VBACKUP GND 4
C1
Pin Configurations appear at end of data sheet. UL is a registered trademark of Underwriters Laboratories Inc.
Benefits and Features
Enhanced Second Source for the ST M41T00
Completely Manages All Timekeeping Functions
RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year
Software Clock Calibration Oscillator Stop Flag
Low-Power Operation Extends Battery Backup Run
Time Low Tim...
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