A =No Acknowledge(SDA High)

A = Acknowledge

S=StartCondition

P =StopCondition

W=Write

R=Read

A

A

A

P

DATA

DATA

S

Slave Address

FromTransmitter

FromReceiver

W

A6

A5

2

A0

A1

ACK

Acknowledge

(FromReceiver)

ICDevice Addressand

Read/WriteBit

R/W

D7

D6

D0

D0

ACK

Stop

Condition

Acknowledge

(Receiver)

LastDataByte

SDA

D7

D6

D1

D1

FirstData

Byte

Start

Condition

Acknowledge

(Transmitter)

ACK

Other

DataBytes

A =No Acknowledge(SDA High)

A = Acknowledge

S=StartCondition

P =StopCondition

W=Write

R=Read

A

A

A

P

DATA

DATA

S

Slave Address

Transmitter

Receiver

R

A6

2

A0

ACK

Acknowledge

(From

Receiver)

ICDevice Addressand

Read/WriteBit

R/W

D7

D0

ACK

Stop

Condition

Acknowledge

(From

Transmitter)

LastDataByte

SDA

D7

D6

D1

D0

ACK

FirstData

Byte

Start

Condition

Not

Acknowledge

(Transmitter)

Other

DataBytes

THS7347

SLOS531B

– MAY 2007 – REVISED OCTOBER 2011

www.ti.com

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 WRITE

AND READ EXAMPLES for more information.

Figure 9. I2C Write Cycle

Figure 10. Multiple Byte Write Transfer

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 WRITE AND READ EXAMPLES for more information.

Figure 11. I2C Read Cycle

Figure 12. Multiple Byte Read Transfer

18

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© 2007–2011, Texas Instruments Incorporated