NXP Semiconductors
PCF2127
Accurate RTC with integrated quartz crystal for industrial applications
8.9.5 Register Weekdays
Table 36. Weekdays - weekdays register (address 07h) bit allocation
Bit positions labeled as - are not implemented and return 0 when read. Bits labeled as X are undefined at power-on and
unchanged by subsequent resets.
Bit
7
6
5
4
3
2
1
0
Symbol
-
-
-
-
-
WEEKDAYS (0 to 6)
Reset
-
-
-
-
-
X
X
X
value
Table 37. Weekdays - weekdays register (address 07h) bit description
Bit positions labeled as - are not implemented and return 0 when read. Bits labeled as X are undefined at power-on and
unchanged by subsequent resets.
Bit
Symbol
Value
Description
7 to 3
-
-
unused
2 to 0
WEEKDAYS
0 to 6
actual weekday value, see Table 38
Although the association of the weekdays counter to the actual weekday is arbitrary, the
PCF2127 assumes that Sunday is 000 and Monday is 001 for the purpose of determining
the increment for calendar weeks.
Table 38. Weekday assignments
Day[1]
Bit
2
1
0
Sunday
0
0
0
Monday
0
0
1
Tuesday
0
1
0
Wednesday
0
1
1
Thursday
1
0
0
Friday
1
0
1
Saturday
1
1
0
[1] Definition may be reassigned by the user.
PCF2127
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 8 — 19 December 2014
© NXP Semiconductors N.V. 2014. All rights reserved.
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