PCF2129AT/2,518 NXP Semiconductors, PCF2129AT/2,518 Datasheet - Page 34

• Manufacturer Part Number: PCF2129AT/2,518
• Description: Real Time Clock
• Manufacturer: NXP Semiconductors
• Series: PCF2129r

Specifications of PCF2129AT/2,518

• Rohs: yes
• Function: Clock, Calendar, Alarm, Watchdog, Timestamp
• Rtc Bus Interface: I2C, SPI
• Date Format: Binary
• Time Format: Binary
• Supply Voltage - Max: 4.2 V
• Supply Voltage - Min: 1.2 V
• Maximum Operating Temperature: + 60 C
• Minimum Operating Temperature: - 15 C
• Mounting Style: SMD/SMT
• Package / Case: SOP-20
• Battery Backup Switching: Yes
• Factory Pack Quantity: 2000

NXP Semiconductors
PCF2129AT
Product data sheet
8.11.1 Timestamp flag
8.11 Timestamp function
The PCF2129AT has an active LOW timestamp input pin TS, internally pulled with an
on-chip pull-up resistor to the internal power supply of the device. It also has a timestamp
detection circuit which can detect two different events:
The timestamp function is enabled by default after power-on and it can be switched off by
setting the control bit TSOFF (register Timestp_ctl).
A most common application of the timestamp function is described in
See
1. Input on pin TS is driven to an intermediate level between power supply and ground.
2. Input on pin TS is driven to ground.
1. When the TS input pin is driven to an intermediate level between the power supply
2. When the TS input pin is driven to ground, the following sequence occurs:
Fig 18. Timestamp detection with two push-buttons on the TS pin (for example, for
and ground, then the following sequence occurs:
a. The actual date and time are stored in the timestamp registers.
b. The timestamp flag TSF1 (register Control_1) is set.
c. If the TSIE bit (register Control_2) is active, an interrupt on the INT pin is
The TSF1 flag can be cleared by command. Clearing the flag will clear the interrupt.
Once TSF1 is cleared, it will only be set again when a new negative edge on pin TS is
detected.
a. The actual date and time are stored in the timestamp registers.
b. In addition to the TSF1 flag, the TSF2 flag (register Control_2) is set.
c. If the TSIE bit is active, an interrupt on the INT pin is generated.
Section 8.12.5
generated.
tamper detection)
All information provided in this document is subject to legal disclaimers.
push-button 2
connected to
cover 2
for a description of interrupt generation from the timestamp function.
Rev. 5 — 12 February 2013
push-button 1
connected to
cover 1
V
SS
R2 =
220 kΩ
± 5 %
Integrated RTC, TCXO and quartz crystal
TS
1
2
3
4
5
6
7
8
9
10
PCF2129AT
V
DD
R1 =
220 kΩ
(typ)
013aaa681
PCF2129AT
20
19
18
17
16
15
14
13
12
11
Ref. 3
© NXP B.V. 2013. All rights reserved.
“AN10857”.
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