Datasheet

PCF2127AT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6 — 11 July 2013 30 of 86
NXP Semiconductors
PCF2127AT
Integrated RTC, TCXO and quartz crystal
8.9 Time and date function
Most of these registers are coded in the Binary Coded Decimal (BCD) format.
8.9.1 Register Seconds
[1] Start-up value.
8.9.2 Register Minutes
Table 20. Seconds - seconds and clock integrity register (address 03h) bit description
Bit Symbol Value Place value Description
7 OSF 0 - clock integrity is guaranteed
1
[1]
- clock integrity is not guaranteed:
oscillator has stopped and chip reset
has occurred since flag was last cleared
6 to 4 SECONDS 0 to 5 ten’s place actual seconds coded in BCD format
3to0 0to9 unit place
Table 21. Seconds coded in BCD format
Seconds value in
decimal
Upper-digit (ten’s place) Digit (unit place)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
00 0000000
01 0000001
02 0000010
: :::::::
09 0001001
10 0010000
: :::::::
58 1011000
59 1011001
Table 22. Minutes - minutes register (address 04h) 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
3to0 0to9 unit place