LNBH25

I²C interface protocol

Doc ID 022433 Rev 4

19/34

7.2

Read mode transmission

In Read mode the bytes sequence must be as follows:

●

a start condition (S)

●

a chip address byte with the LSB bit R/W=0

●

the register address byte of the internal first register to be accessed

●

a stop condition (P)

●

a new master transmission with the chip address byte and the LSB bit R/W=1

●

after the acknowledge the LNBH25 starts to send the addressed register content. As

long as the master keeps the acknowledge LOW, the LNBH25 transmits the next

address register byte content.

●

the transmission is terminated when the master sets the acknowledge HIGH with a

following stop bit.

Figure 12.

ACK = Acknowledge

S = Start

P = Stop

R/W = 1/0, Read/Write bit

X = 0/1, set the values to select the CHIP ADDRESS (see Chip Address in

Table 16 for pin

selection) and to select the REGISTER Address (see

Table 7).

b.

The reading procedure can start from any register address (Status 1, 2 or Data1..4) by simply setting the X

values in the register address byte (after the first Chip Address in the above figure). It can be also stopped from

the master by sending a stop condition after any acknowledge bit.

AM09914v2

S

XX

P

00

X

00

0

X

0

0

1

0

0

0

S

XX

P

00

X

00

0

X

0

1

0

0

0

P

P

MSB

LSB

DATA 1

Add=0x2

MSB

LSB

DATA 2

Add=0x3

MSB

LSB

DATA 3

Add=0x4

MSB

LSB

DATA 4

Add=0x5

MSB

LSB

DATA 1

Add=0x2

MSB

LSB

DATA 2

Add=0x3

MSB

LSB

DATA 3

Add=0x4

MSB

LSB

DATA 4

Add=0x5

MSB

LSB

STATUS 2

Add=0x1

MSB

LSB

STATUS 1

Add=0x0

MSB

LSB

STATUS 2

Add=0x1

MSB

LSB

STATUS 1

Add=0x0

SX

0

0

1

0

0

0

SX

0

1

0

0

0

MSB

LSB

CHIP ADDRESS

MSB

LSB

REGISTER ADDRESS

MSB

LSB

CHIP ADDRESS