Datasheet

AD7991/AD7995/AD7999

Rev. B | Page 23 of 28

WRITING TO THE AD7991/AD7995/AD7999

By default, each part operates in read-only mode and all four chan-

nels are selected as enabled in the configuration register. To write

to the AD7991/AD7995/AD7999 configuration register, the user

must first address the device.

The configuration register is an 8-bit register; therefore, only

one byte of data can be written to this register. However, writing

a single byte of data to this register consists of writing the serial

bus write address, followed by the data byte written (see Figure 24).

SCL

SDA

START BY

MASTER

ACK BY

ADC

R/W

FRAME 1

SERIAL BUS ADDRESS BYTE

CONFIGURATION REGISTER BYTE

ACK BY

ADC

STOP

0 0 0 0 A0 D7 D6 D5 D4 D3 D2 D1 D011

991

06461-026

Figure 24. Writing to the AD7991/AD7995/AD7999 Configuration Register