I²C interface protocol

LNBH25LS

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DocID026753 Rev 3

7

I²C interface protocol

7.1

Write mode transmission

The LNBH25S interface protocol is made up of:



A start condition (S)



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



A register address (internal address of the first register to be accessed)



A sequence of data (byte to write to the addressed internal register + acknowledge)



The following bytes, if any, to be written to successive internal registers



A stop condition (P). The transfer lasts until a stop bit is encountered



The LNBH25S, as slave, acknowledges every byte transfer

Figure 10: Example of writing procedure starting with first data address 0X2

ACK = acknowledge

S = start

P = stop

R/W = 1/0, read/write bit

X = 0/1, set the values to select the chip address.

The writing procedure can start from any register address by simply setting X

values in the register address byte (after the chip address). It can be also stopped

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

7.2

Read mode transmission

In read mode the byte sequence 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 acknowledge, the LNBH25S starts to send the addressed register content. As

long as the master keeps the acknowledge low, the LNBH25S transmits the next

address register byte content