THS7347 Datasheet, PDF (18/28 Pages) Texas Instruments – 3-Channel RGBHV Video Buffer with I2C™ Control, 2:1 Input Mux, Monitor Pass-Through, and Selectable Input Bias Modes

THS7347
SLOS531 – MAY 2007
www.ti.com
APPLICATIONS INFORMATION (continued)
During a write cycle, the transmitting device must not drive the SDA signal line during the acknowledge cycle, so
that the receiving device may drive the SDA signal low. After each byte transfer following the address byte, the
receiving device pulls the SDA line low for one SCL clock cycle. A stop condition is initiated by the transmitting
device after the last byte is transferred. Figure 9 and Figure 10 show an example of a write cycle. Note that the
THS7347 does not allow multiple write transfers to occur. See the example, Writing to the THS7347, in
Section 12 for more information.
From Receiver
S Slave Address
W A DATA A DATA A P
From Transmitter
Figure 9. I²C Write Cycle
A = No Acknowledge (SDA High)
A = Acknowledge
S = Start Condition
P = Stop Condition
W = Write
R = Read
Start
Condition
Acknowledge
(From Receiver)
Acknowledge
(Receiver)
Acknowledge
(Transmitter)
SDA
A6 A5
A1 A0 R/W ACK D7 D6
D1 D0 ACK
D7 D6
D1 D0 ACK
I²C Device Address and
Read/Write Bit
First Data
Byte
Other
Last Data Byte
Data Bytes
Figure 10. Multiple Byte Write Transfer
Stop
Condition
During a read cycle, the slave receiver acknowledges the initial address byte if it decodes the address as its
address. Following this initial acknowledge by the slave, the master device becomes a receiver and
acknowledges data bytes sent by the slave. When the master has received all of the requested data bytes from
the slave, the not acknowledge (A) condition is initiated by the master by keeping the SDA signal high just
before it asserts the stop (P) condition. This sequence terminates a read cycle, as shown in Figure 11 and
Figure 12. Note that the THS7347 does not allow multiple read transfers to occur. See the example, Reading
from the THS7347, in Section 12 for more information.
S Slave Address R A DATA A DATA A P
Transmitter
Receiver
Figure 11. I²C Read Cycle
A = No Acknowledge (SDA High)
A = Acknowledge
S = Start Condition
P = Stop Condition
W = Write
R = Read
Start
Condition
Acknowledge
(From
Receiver)
Acknowledge
(From
Transmitter)
Not
Acknowledge
(Transmitter)
SDA
A6
A0 R/W ACK D7
D0 ACK
D7 D6
D1 D0 ACK
I²C Device Address and
Read/Write Bit
First Data
Byte
Other
Last Data Byte
Data Bytes
Figure 12. Multiple Byte Read Transfer
Stop
Condition
18
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