TLC59208F_1 Datasheet, PDF (20/29 Pages) Texas Instruments – 8-BIT FM+ I2C BUS LED DRIVER

TLC59208F
SCLS715 – MARCH 2009 .................................................................................................................................................................................................. www.ti.com
System Configuration
A device generating a message is a transmitter; a device receiving is the receiver. The device that controls the
message is the master and the devices which are controlled by the master are the slaves (see Figure 11).
SDA
SCL
Master
Transmitter/
Receiver
Slave Receiver
Slave
Transmitter/
Receiver
Master
Transmitter
Master
Transmitter/
Receiver
I²C Bus
Multiplexer
Slave
Figure 11. System Configuration
Acknowledge
The number of data bytes transferred between the Start and the Stop conditions from transmitter to receiver is
not limited. Each byte of eight bits is followed by one acknowledge bit. The acknowledge bit is a high level put on
the bus by the transmitter, whereas the master generates an extra acknowledge related clock pulse.
A slave receiver which is addressed must generate an acknowledge after the reception of each byte. Also a
master must generate an acknowledge after the reception of each byte that has been clocked out of the slave
transmitter. The device that acknowledges has to pull down the SDA line during the acknowledge clock pulse, so
that the SDA line is stable low during the high period of the acknowledge related clock pulse; set-up time and
hold time must be taken into account.
A master receiver must signal an end of data to the transmitter by not generating an acknowledge on the last
byte that has been clocked out of the slave. In this event, the transmitter must leave the data line high to enable
the master to generate a Stop condition.
Data Output
by Transmitter
Data Output
by Receiver
NACK
ACK
SCL From
Master
S
Start
Condition
1
2
8
9
Figure 12. Acknowledge on I²C Bus
Clock Pulse for
Acknowledgment
20
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