M41T80(2002) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

M41T80
(Rev.:2002)

SERIAL ACCESS RTC WITH ALARMS

STMicroelectronics 

M41T80

SUMMARY DESCRIPTION

The M41T80 Serial Access TIMEKEEPER®

SRAM is a low power Serial RTC with a built-in

32.768 KHz oscillator (external crystal controlled).

Eight registers (see Table 8, page 13) are used for

the clock/calendar function and are configured in

binary coded decimal (BCD) format. An additional

12 registers provide status/control of Alarm, 32kHz

output, and Square Wave functions. Addresses

and data are transferred serially via a two line, bi-

directional I2C interface. The built-in address reg-

ister is incremented automatically after each

WRITE or READ data byte.

Functions available to the user include a time-of-

day clock/calendar, Alarm interrupts, 32kHz out-

put, and programmable Square Wave output. The

eight clock address locations contain the century,

year, month, date, day, hour, minute, second and

tenths/hundredths of a second in 24 hour BCD for-

mat. Corrections for 28, 29 (leap year - valid until

year 2100), 30 and 31 day months are made auto-

matically.

The M41T80 is supplied in an 8-pin SOIC.

Figure 3. 8-pin SOIC Connections

XI

XO

F32k(1)

VSS

1

8

2

7

3 M41T80 6

4

5

VCC

IRQ/OUT/SQW(1)

SCL

SDA

AI07006

Note: 1. Open drain output.

Figure 4. Block Diagram

CRYSTAL

SDA

SCL

Note: 1. Open Drain output

32KHz

OSCILLATOR

I2C

INTERFACE

REAL TIME CLOCK

CALENDAR

RTC W/ALARM

AF

SQUARE WAVE

IRQ/OUT/SQW(1)

F32k(1)

AI07007

3/20

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