RV-3029 Datasheet, PDF (47/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
6. I²C INTERFACE
The I²C interface is for bidirectional, two lines communication between different ICs or modules. The two lines are a
Serial-DAtaline (SDA) and a Serial-CLockline (SCL).
6.1. I²C INTERFACE CHARACTERISTICS
SCL and SDA ports are open-drain architecture to allow connections of multiple devices. Both lines must be
connected to a positive supply via pull-up resistors.
6.2. I²C INTERFACE SYSTEM CONFIGURATION
Since multiple devices can be connected with the I²C bus, all I²C bus devices have a fixed, unique device number
built-in to allow individual addressing of each device.
Data transfer may be initiated only when the bus is not busy.
The device that controls the I²C bus is the “Master”; the devices which are controlled by the master are the
“Slaves”. A device generating a message is a “Transmitter”; a device receiving a message is the “Receiver”.
The communication is controlled by the Master. To start a transmission, the Master applies the “START condition”
and generates the SCL clocks during the whole transmission. Before any data is transmitted on the I²C bus, the
device which should respond is addressed first. The addressing is always carried out with the first byte transmitted
after the “START condition”, most significant bit MSB is sent first. The master terminates the transmission by
sending the “STOP condition”.
The RV-3029 acts as a Slave-Receiver or Slave-Transmitter. Therefore the clock signal SCL is only an input signal,
but the data signal SDA is a bidirectional line.
Application Diagram
Pull-up Resistors
R = ^tr
C_bus
VDD
INT
I²C-Bus
Master ^SCL
SDA
RV-3029
Slave address:
Write: AC
Read: AD
I²C-Bus
Device
I²C-Bus
Device
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