M41TC8025CMC7F datasheet(15/41 Pages) STMICROELECTRONICS

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M41TC8025

Operation

2.4

Clock and calendar

The M41TC8025 incorporates an accurate temperature-compensated real-time clock and

calendar. The user can access at registers 00h to 06h.

2.4.1

Clock registers configuration

The clock counters count seconds, minutes, and hours. The data is in BCD format. For

example, the "seconds" register value "0101 1001" indicates 59 seconds.

The seconds and minutes counters count from "00" to "01", "02" and up to "59" and they roll

over to "00" after that.

The hours counter counts from "00" to "01", "02" and up to "23" and it rolls over to "00" after

that.

Note:

Writing invalid time data may interfere with normal operation of the clock counter.

2.4.2

Calendar registers configuration

In the day-of-week register, each bit (from bit 0 to bit 6) represents a different day of the

week.

The day-of-week data values sequence is as follows: Day 01h

 Day 02h  Day 04h 

Day 08h

 Day 10h  Day 20h  Day 40h  Day 01h  Day 02h, etc. The possible

configuration in the Day-of-week register is in Table 7 .

Table 5. Clock counters (00h to 02h)

Address

Function

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

00h

Seconds

01h

Minutes

02h

Hours

Table 6. Calendar counters (03h to 06h)

Address

Function

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

03h

Day-of-week

4321

04h

Date (day of month)

05h

Month

06h

Year

Obsolete

Product(s)

- Obsolete

Product(s)

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