TMDS261B Datasheet, PDF (37/48 Pages) Texas Instruments – TWO-PORT HDMI SWITCH

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TMDS261B
SLLS987A – SEPTEMBER 2009 – REVISED JULY 2011
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SCL
SDA
MSB
Acknowledge
Slave Address
Data
Stop
Acknowledge
T0396-01
Figure 53. I²C Address, Data Cycle(s), and Stop
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. An example of a write cycle can be found in Figure 54 and Figure 55.
Note that the TMDS261B allows multiple write transfers to occur. See the Example – Writing to the TMDS261
section for more information.
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 56 and Figure 57.
See the Example – Reading from the TMDS261 section for more information.
S Slave Address
From Receiver
W A Data A Data A P
A = No Acknowledge (SDA High)
A = Acknowledge
S = Start Condition
P = Stop Condition
W = Write
From Transmitter
R0007-01
Figure 54. I²C Write Cycle
Start
Condition
Acknowledge
(From Receiver)
Acknowledge
(Receiver)
Acknowledge
(Receiver)
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 55. Multiple-Byte Write Transfer
Stop
Condition
T0397-01
S Slave Address R A Data A Data A P
Transmitter
Receiver
A = No Acknowledge (SDA High)
A = Acknowledge
S = Start Condition
P = Stop Condition
W = Write
R = Read
R0008-01
Figure 56. I²C Read Cycle
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