AD5392_15 Datasheet, PDF (29/44 Pages) Analog Devices – 8-/16-Channel, 3 V/5 V, Serial Input, Single-Supply, 12-/14-Bit Voltage Output

Data Sheet
3-BYTE MODE
The 3-byte mode lets the user update more than one channel in
a write sequence without having to write the device address byte
each time. The device address byte is required only once and
subsequent channel updates require the pointer byte and the
data bytes. In 3-byte mode, the user begins with an address byte
(R/W = 0) after which the DAC acknowledges that it is prepared
to receive data by pulling SDA low. The address byte is followed
by the pointer byte; this addresses the specific channel in the
DAC to be addressed and is also acknowledged by the DAC.
Address Bits A3 to A0 address all channels on the AD5390/
AD5391. Address Bits A2 to A0 address all channels on the
AD5390/AD5391/AD5392
AD5392. Address Bit A3 is a zero on the AD5392. This is then
followed by the two data bytes. REG1 and REG0 determine the
register to be updated.
If a STOP condition is not sent following the data bytes,
another channel can be updated by sending a new pointer
byte followed by the data bytes. This mode requires only three
bytes to be sent to update any channel once the device has
been initially addressed and reduces the software overhead in
updating the AD5390/AD5391/AD5392 channels. A STOP
condition at any time exits this mode. Figure 35 shows a typical
configuration.
SCL
SDA
1
0
1
0
1
AD1 AD0 R/W
A/B
0
0
0
A3
A2
A1 A0
START
CONDITION
BY
MASTER
ADDRESS BYTE
ACK MSB
BY
CONVERTER
POINTER BYTE FOR CHANNEL N
ACK
BY
CONVERTER
SCL
SDA
SCL
SDA
SCL
SDA
REG1 REG0 MSB
MOST SIGNIFICANT DATA BYTE
LSB
MSB
ACK
BY
CONVERTER
DATA FOR CHANNEL N
LEAST SIGNIFICANT DATA BYTE
LSB
ACK
BY
CONVERTER
0
MSB
0
0
0
A3
A2
A1
A0
ACK
BY
POINTER BYTE FOR CHANNEL NEXT CHANNEL ^CONVERTER
REG1 REG0 MSB
MOST SIGNIFICANT DATA BYTE
LSB
MSB
ACK
BY
CONVERTER
LEAST SIGNIFICANT DATA BYTE
DATA FOR CHANNEL NEXT CHANNEL
Figure 35. 3-Byte Mode I²C Write Operation
LSB
ACK
STOP
BY
CONDITION
CONVERTER
BY
MASTER
Rev. F | Page 29 of 44