PCF2129AT/2,518 NXP Semiconductors, PCF2129AT/2,518 Datasheet - Page 48

• 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
9.2.1 Bit transfer
9.2.2 START and STOP conditions
9.2.3 System configuration
9.2 I
The I
The two lines are a Serial DAta line (SDA) and a Serial CLock line (SCL). Both lines are
connected to a positive supply by a pull-up resistor. Data transfer is initiated only when the
bus is not busy.
One data bit is transferred during each clock pulse. The data on the SDA line remains
stable during the HIGH period of the clock pulse as changes in the data line at this time
are interpreted as control signals (see
Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW
transition of the data line, while the clock is HIGH, is defined as the START condition S. A
LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the STOP
condition P (see
Remark: For the PCF2129AT, a repeated START is not allowed. Therefore a STOP has
to be released before the next START.
A device generating a message is a transmitter; a device receiving a message is the
receiver. The device that controls the message is the master; and the devices which are
controlled by the master are the slaves.
The PCF2129AT can act as a slave transmitter and a slave receiver.
2
Fig 31. Bit transfer
Fig 32. Definition of START and STOP conditions
C-bus interface
2
C-bus is for bidirectional, two-line communication between different ICs or modules.
SDA
SCL
START condition
All information provided in this document is subject to legal disclaimers.
Figure
SDA
SCL
S
Rev. 5 — 12 February 2013
32).
data valid
data line
stable;
Figure
31).
Integrated RTC, TCXO and quartz crystal
allowed
change
of data
STOP condition
PCF2129AT
mbc621
P
© NXP B.V. 2013. All rights reserved.
mbc622
SDA
SCL
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