PCF2127AT/1 NXP [NXP Semiconductors], PCF2127AT/1 Datasheet - Page 31

• Manufacturer Part Number: PCF2127AT/1
• Description: Integrated RTC, TCXO and quartz crystal
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCF2127A_2
Product data sheet
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
As a consequence 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 may 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. Therefore it is
advised to read all time and date registers in one access.
Fig 17. Data flow of the time function
Fig 18. Access time for read/write operations
START
All information provided in this document is subject to legal disclaimers.
SLAVE ADDRESS
12_24 hour mode
Rev. 02 — 7 May 2010
CALCULATION
LEAP YEAR
Figure
18).
DATA
SECONDS
MINUTES
MONTHS
1 Hz tick
HOURS
YEARS
DAYS
Integrated RTC, TCXO and quartz crystal
DATA
t < 1 s
WEEKDAY
001aaf901
PCF2127A
STOP
© NXP B.V. 2010. All rights reserved.
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