AD7294 datasheet(33/45 Pages) AD

33 / 45 page

Preliminary Technical Data

AD7294

Reading Data from an 8-Bit Register

Reading the contents from any of the 8-bit registers is a single-

byte read operation, as shown in Figure 30. This protocol

assumes that the particular register address has been set up by a

single-byte write operation to the address pointer register (see

Figure 30). Once the register address has been set up, any

number of reads can be performed from that particular register

without having to write to the address pointer register again. If a

read from a different address is required, the relevant register

address has to be written to the address pointer register, and

again any number of reads from this register can then be

performed. In this operation, the master device receives a single

byte from a slave device as follows:

The master device asserts a start condition on SDA.

The master sends the 7-bit slave address followed by

the read bit (high).

The addressed slave device asserts ACK on SDA.

The master receives a data byte.

The master asserts NACK on SDA so that the slave

knows the data transfer is complete.

The master asserts a stop condition on SDA, and the

transaction ends.

SDA

R/W

SC L

START BY

MASTER

ACK. BY

AD7294

NO ACK. BY

MASTER

STOP BY

MASTER

FRAME 1

SERIAL BUS ADDRESS BYT E

FRAME 2

SINGLE DATA BYT E FROM AD7294

Figure 30. Reading a Single Byte of Data from a Selected Register

Rev. PrB | Page 33 of 45

AD7294 데이터시트(PDF) 33 Page - Analog Devices