PCF2127 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF2127' PDF : 101 Pages View PDF
NXP Semiconductors
PCF2127
Accurate RTC with integrated quartz crystal for industrial applications
8.10.5 Register Weekday_alarm
Table 52. Weekday_alarm - weekday alarm register (address 0Eh) 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
AE_W
-
-
-
-
WEEKDAY_ALARM (0 to 6)
Reset
1
-
-
-
-
X
X
X
value
Table 53. Weekday_alarm - weekday alarm register (address 0Eh) 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
AE_W
0
weekday alarm is enabled
1
weekday alarm is disabled
6 to 3
-
-
unused
2 to 0
WEEKDAY_ALARM
0 to 6
weekday alarm information
8.10.6 Alarm flag
When all enabled comparisons first match, the alarm flag AF (register Control_2) is set.
AF remains set until cleared by command. Once AF has been cleared, it will only be set
again when the time increments to match the alarm condition once more. For clearing the
flags, see Section 8.11.6
Alarm registers which have their alarm enable bit AE_x at logic 1 are ignored.
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PLQXWHDODUP
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DDI
Example where only the minute alarm is used and no other interrupts are enabled.
Fig 22. Alarm flag timing diagram
8.11 Timer functions
The PCF2127 has two different timer functions, a watchdog timer and a countdown timer.
The timers can be selected by using the control bits WD_CD[1:0] in the register
Watchdg_tim_ctl.
• The watchdog timer has four selectable source clocks. It can, for example, be used to
detect a microcontroller with interrupt and reset capability which is out of control (see
Section 8.11.3)
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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