PCF2127AT/1,518 NXP Semiconductors, PCF2127AT/1,518 Datasheet - Page 36
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PCF2127AT/1,518
Manufacturer Part Number
PCF2127AT/1,518
Description
IC RTC/CALENDAR TCXO QTZ 20SOIC
Manufacturer
NXP Semiconductors
Type
Clock/Calendar/Alarmr
Datasheet
1.PCF2127AT1518.pdf
(80 pages)
Specifications of PCF2127AT/1,518
Package / Case
20-SOIC (0.300", 7.50mm Width)
Time Format
HH:MM:SS (12/24 hr)
Memory Size
512B
Date Format
YY-MM-DD-dd
Interface
I²C, 2-Wire Serial
Voltage - Supply
1.8 V ~ 4.2 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Function
Serial Clock, Timestamp, Timekeeper, Watchdog, Alarm, Calendar, Timer, Timer Interrupt
Rtc Memory Size
512 bytes
Supply Voltage (max)
4.2 V
Supply Voltage (min)
1.8 V
Mounting Style
SMD/SMT
Rtc Bus Interface
I2C
Supply Current
2600 nA
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
NXP Semiconductors
PCF2127A_2
Product data sheet
8.11.2 Register Watchdg_tim_val
8.11.3 Watchdog timer function
Table 35.
Table 36.
The watchdog timer function is controlled by the WD_CD[1:0] bits of the register
Watchdg_tim_ctl (see
The two bits TF[1:0] in register Watchdg_tim_ctl determine one of the four source clock
frequencies for the watchdog timer: 4.096 kHz, 64 Hz, 1 Hz, or
When the watchdog timer function is enabled, the 8 bit timer in register Watchdg_tim_val
(see
The watchdog timer counts down from the software programmed 8 bit binary value n in
register Watchdg_tim_val. When the counter reaches 1 the watchdog timer flag WDTF
(register Control_2) is set logic 1.
In the case that WDTF is logic 1:
The counter does not automatically reload.
When WD_CD[1:0] = 10 or WD_CD[1:0] = 11 and the microcontroller unit (MCU) loads a
watchdog timer value n:
Loading the counter with 0 will:
Bit
7 to 0 WATCHDG_TIM_VAL[7:0]
TF[1:0] Timer source
00
01
10
11
•
•
•
•
•
•
•
•
if WD_CD[1:0] = 10 an interrupt will be generated
if WD_CD[1:0] = 11 a reset will be generated
the flag WDTF is reset
INT or RST is cleared
the watchdog timer starts again
reset the flag WDTF
clear INT or RST
stop the watchdog timer
Table
Symbol
clock frequency
4.096
64
1
1
⁄
60
Watchdg_tim_val - watchdog timer value register (address 11h) bit description
Programmable watchdog or countdown timer
35) determines the watchdog timer period.
All information provided in this document is subject to legal disclaimers.
Table
Rev. 02 — 7 May 2010
34).
Units
kHz
Hz
Hz
Hz
Value
00 to FF countdown period in seconds:
Minimum timer
period (n = 1)
244
15.625
1
60
Description
where n is the countdown value
CountdownPeriod
Integrated RTC, TCXO and quartz crystal
Units
μs
ms
s
s
=
Maximum timer
period (n = 255)
62.256
3.984
255
15300
1
-------------------------------------------------------------- -
SourceClockFrequency
⁄
60
PCF2127A
Hz (see
© NXP B.V. 2010. All rights reserved.
n
Table
36).
Units
ms
s
s
s
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