Datasheet

AD5273
Rev. H | Page 18 of 24
4. When all data bits have been read or written, a stop con-
dition is established by the master. A stop condition is
defined as a low-to-high transition on the SDA line
while SCL is high. In write mode, the master pulls the
SDA line high during the 10
th
clock pulse to establish a
stop condition, as shown in Figure 42 and Figure 43. In
read mode, the master issues a no acknowledge for the
ninth clock pulse, that is, the SDA line remains high. The
master then brings the SDA line low before the 10
th
clock
pulse, which goes high to establish a stop condition, as
shown in Figure 44.
A repeated write function gives the user flexibility to
update the RDAC output continuously, except after
permanent programming, when the part is addressed and
receives instructions only once. During the write cycle,
each data byte updates the RDAC output. For example,
after the RDAC has acknowledged its slave address and
instruction bytes, the RDAC output updates after these two
bytes. If another byte is written to the RDAC while it is still
addressed to a specific slave device with the same instruc-
tion, this byte updates the output of the selected slave device.
If different instructions are needed, the write mode must
be started again with a new slave address, instruction, and
data bytes. Similarly, a repeated read function of the RDAC
is also allowed.
CONTROLLING TWO DEVICES ON ONE BUS
Figure 45 shows two AD5273 devices on the same serial bus.
Each has a different slave address because the state of each AD0
pin is different. This allows each device to operate independently.
The master device output bus line drivers are open-drain pull-
down in a fully I
2
C-compatible interface.
MASTER
SDA
SCL
AD0
AD5273
SDA
SCL
AD0
AD5273
SDA
SCL
5
V
R
P
R
P
5V
03224-045
Figure 45. Two AD5273 Devices on One Bus