PCF8563
NXP Semiconductors
Real-time clock/calendar
The VL flag is intended to detect the situation when VDD is decreasing slowly, for example
under battery operation. Should the oscillator stop or VDD reach Vlow before power is
re-asserted, then the VL flag is set. This will indicate that the time may be 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
unit place
actual minutes coded in BCD format
3 to 0
0 to 9
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
3 to 0
0 to 2
0 to 9
ten’s place
unit place
actual hours coded in BCD format
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
0 to 9
ten’s place
unit place
actual day coded in BCD format
3 to 0
[1] The PCF8563 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
PCF8563
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Product data sheet
Rev. 10 — 3 April 2012
11 of 50
NXP [ NXP ]
