PCF85063ATTSLASHAJ datasheet(22/55 Pages) NXP

22 / 55 page

NXP Semiconductors

PCF85063A

Tiny Real-Time Clock/calendar with alarm function and I2C-bus

aaa-004421

SECONDS

1 Hz tick

MINUTES

HOURS

12_24 hour mode

DAYS

WEEKDAY

LEAP YEAR

CALCULATION

MONTHS

YEARS

Figure 14. Data flow for the time function

During read/write operations, the time counting circuits (memory locations 04h through 0Ah) are blocked.

The blocking prevents

• Faulty reading of the clock and calendar during a carry condition

• Incrementing the time registers during the read cycle

After this read/write access is completed, the time circuit is released again and any pending request to

increment the time counters that occurred during the read/write access is serviced. A maximum of 1 request can

be stored; therefore, all accesses must be completed within 1 second (see Figure 15).

aaa-004422

t < 1 s

START

DATA

STOP

SLAVE ADDRESS

Figure 15. Access time for read/write operations

Because of this method, it is very important to make a read or write access in one go, that is, setting or reading

seconds through to years should be made in one single access. Failing to comply with this method could result

in the time becoming corrupted.

As an example, if the time (seconds through to hours) is set in one access and then in a second access the

date is set, it is possible that the time will increment between the two accesses. A similar problem exists when

reading. A roll-over may occur between reads thus giving the minutes from one moment and the hours from the

next.

Recommended method for reading the time:

1. Send a START condition and the slave address (see Table 38) for write (A2h)

2. Set the address pointer to 4 (Seconds) by sending 04h

3. Send a RESTART condition or STOP followed by START

4. Send the slave address for read (A3h)

5. Read Seconds

6. Read Minutes

PCF85063A

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 7.1 — 8 November 2023

22 / 55

PCF85063ATT/AJ 数据表(PDF) 22 Page - NXP Semiconductors

PCF85063ATT/AJ 数据表(HTML) 22 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

数据表下载