3/15

M41T00

Table 3. Register Map

Note: 1. When CEB is set to ’1’, CB will toggle from ’0’ to ’1’ or from ’1’ to ’0’ at the turn of the century (dependent upon the initial value set).

When CEB is set to ’0’, CB will not toggle.

Address

Data

Function/Range

BCD Format

D7

D6

D5

D4

D3

D2

D1

D0

0

ST

10 Seconds

Seconds

Seconds

00-59

1

X

10 Minutes

Minutes

Minutes

00-59

2

CB

10 Hours

Hours

Century/Hour

0-1/00-23

3

XXXXX

Day

Day

01-07

4

X

X

10 Date

Date

Date

01-31

5

X

X

X

10 M.

Month

Month

01-12

6

10 Years

Years

Year

00-99

7

OUT

FT

S

Calibration

Control

Figure 3. Block Diagram

AI00603

SECONDS

OSCILLATOR

32.768 kHz

VOLTAGE

SENSE and

SWITCH

CIRCUITRY

SERIAL

BUS

INTERFACE

DIVIDER

CONTROL

LOGIC

ADDRESS

REGISTER

MINUTES

CENTURY/HOURS

DAY

DATE

MONTH

YEAR

CONTROL

OSCI

OSCO

FT/OUT

VCC

VSS

VBAT

SCL

SDA

1 Hz

Keys:

S = SIGN Bit

FT = FREQUENCY TEST Bit

ST = STOP Bit

OUT = Output level

X = Don’t care

CEB = Century Enable Bit

CB = Century Bit