PCF2129AT/1,512 NXP Semiconductors, PCF2129AT/1,512 Datasheet - Page 30

• Manufacturer Part Number: PCF2129AT/1,512
• Description: IC REAL TIME CLK/CALENDAR 20SOIC
• Manufacturer: NXP Semiconductors
• Type: Clock/Calendar/Alarmr

Specifications of PCF2129AT/1,512

• Package / Case: 20-SOIC (7.5mm Width)
• Date Format: YY-MM-DD-dd
• Time Format: HH:MM:SS (12/24 hr)
• Interface: I²C, SPI
• Voltage - Supply: 1.8 V ~ 4.2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Function: Clock, Alarm, Watchdog, Timestamp
• Supply Voltage (max): 4.2 V
• Supply Voltage (min): 1.8 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: I2C, SPI
• Supply Current: 800 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 568-4960-5; 935288599512

NXP Semiconductors
PCF2129A_2
Product data sheet
8.10.1 Register Watchdg_tim_ctl
8.10.2 Register Watchdg_tim_val
8.10 Timer functions
The PCF2129A has a watchdog timer function. The timer can be switched on and off by
using the control bit WD_CD in the register Watchdg_tim_ctl.
The watchdog timer has four selectable source clocks. It can, for example, be used to
detect a microprocessor with interrupt and reset capability which is out of control (see
Section
To control the timer function and timer output, the registers Control_2, Watchdg_tim_ctl,
and Watchdg_tim_val are used.
Table 30.
[1]
[2]
Table 31.
Bit
7
6
5
4 to 2 -
1 to 0 TF[1:0]
Bit
7 to 0 WATCHDG_TIM_VAL[7:0]
Default value.
When writing to the register this bit has always to be set logic 0.
Symbol
WD_CD
T
TI_TP
Symbol
8.10.3)
Watchdg_tim_ctl - watchdog timer control register (address 10h) bit description
Watchdg_tim_val - watchdog timer value register (address 11h) bit description
All information provided in this document is subject to legal disclaimers.
Rev. 02 — 7 May 2010
Value
0
1
0
0
1
-
00
01
10
11
[1]
[2]
[1]
[1]
Value
00 to FF countdown period in seconds:
Description
watchdog timer disabled
watchdog timer enabled;
unused
the interrupt pin INT is configured to generate a
permanent active signal when MSF (register Control_2)
is set
the interrupt pin INT is configured to generate a pulsed
signal when MSF flag is set (see
unused
timer source clock for watchdog timer
the interrupt pin INT is activated when timed out
4.096 kHz
64 Hz
1 Hz
1
⁄
60
Hz
Description
where n is the countdown value
CountdownPeriod
Integrated RTC, TCXO and quartz crystal
=
-------------------------------------------------------------- -
SourceClockFrequency
PCF2129A
Figure
© NXP B.V. 2010. All rights reserved.
n
19)
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