PCF85063BTL All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved.
Product data sheet Rev. 6 — 18 November 2015 24 of 58
NXP Semiconductors
PCF85063BTL
Tiny Real-Time Clock/calendar with alarm function and SPI-bus
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 read command with register address pointing to 4 (Seconds) by sending 04h
2. Read Seconds
3. Read Minutes
4. Read Hours
5. Read Days
6. Read Weekdays
7. Read Months
8. Read Years
8.5 Alarm registers
8.5.1 Register Second_alarm
[1] Default value.
Fig 13. Access time for read/write operations
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Table 29. Second_alarm - second alarm register (address 0Bh) bit description
Bit Symbol Value Place value Description
7 AEN_S second alarm
0 - enabled
1
[1]
- disabled
6 to 4 SECOND_ALARM 0
[1]
to 5 ten’s place second alarm information
coded in BCD format
3 to 0 0
[1]
to 9 unit place
