PCF8564A_10 Datasheet, PDF (10/45 Pages) NXP Semiconductors – Real time clock and calendar

NXP Semiconductors
PCF8564A
Real time clock and calendar
The VL flag is intended to detect the situation when V_DD is decreasing slowly, for example
under battery operation. Should the oscillator stop or V_DD reach V_low before power is
re-asserted, then the VL flag will be set. This indicates that the time is possibly corrupted.
8.4.2 Register Minutes
Table 10. Minutes - minutes register (address 03h) bit description
Bit Symbol Value Place value Description
7
-
-
-
unused
6 to 4 MINUTES 0 to 5 ten’s place actual minutes coded in BCD format
3 to 0
0 to 9 unit place
8.4.3 Register Hours
Table 11. Hours - hours register (address 04h) bit description
Bit Symbol Value Place value Description
7 to 6 -
-
-
unused
5 to 4 HOURS 0 to 2 ten’s place actual hours coded in BCD format
3 to 0
0 to 9 unit place
8.4.4 Register Days
Table 12. Days - days register (address 05h) bit description
Bit Symbol Value Place value Description
7 to 6 -
-
-
unused
5 to 4 DAYS^[1] 0 to 3 ten’s place actual day coded in BCD format
3 to 0
0 to 9 unit place
[1] The PCF8564A compensates for leap years by adding a 29th day to February if the year counter contains a
value which is exactly divisible by 4, including the year 00.
8.4.5 Register Weekdays
Table 13. Weekdays - weekdays register (address 06h) bit description
Bit Symbol
Value Description
7 to 3 -
-
unused
2 to 0 WEEKDAYS
0 to 6 actual weekday values, see Table 14
PCF8564A
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 02 — 30 September 2010
© NXP B.V. 2010. All rights reserved.
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