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
• The countdown timer has four selectable source clocks allowing for countdown
periods from less than 1 ms to more than 4 hours (see Section 8.11.4)
To control the timer functions and timer output, the registers Control_2, Watchdg_tim_ctl,
and Watchdg_tim_val are used.
8.11.1 Register Watchdg_tim_ctl
Table 54. Watchdg_tim_ctl - watchdog timer control register (address 10h) bit allocation
Bit positions labeled as - are not implemented and return 0 when read.
Bit
7
6
5
4
3
2
Symbol
WD_CD[1:0]
TI_TP
-
-
-
Reset
0
0
0
-
-
-
value
1
0
TF[1:0]
1
1
Table 55. Watchdg_tim_ctl - watchdog timer control register (address 10h) bit description
Bit positions labeled as - are not implemented and return 0 when read.
Bit
Symbol
Value
Description
7 to 6
WD_CD[1:0]
00
Watchdog timer disabled;
countdown timer disabled
01
watchdog timer disabled;
countdown timer enabled
if CDTIE is set logic 1, the interrupt pin INT is
activated when the countdown timed out
10
watchdog timer enabled;
the interrupt pin INT is activated when timed out;
countdown timer not available
11
watchdog timer enabled;
the reset pin RST is activated when timed out;
countdown timer not available
5
TI_TP
0
the interrupt pin INT is configured to generate a
permanent active signal when MSF and/or CDTF is
set
1
the interrupt pin INT is configured to generate a
pulsed signal when MSF flag and/or CDTF flag is set
(see Figure 27)
4 to 2
-
-
unused
1 to 0
TF[1:0]
timer source clock for watchdog and countdown timer
00
4.096 kHz
01
64 Hz
10
1 Hz
11
1⁄60 Hz
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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