X9438 Datasheet, PDF (5/18 Pages) Intersil Corporation – Dual Digitally Controlled Potentiometer (XDCP) with Operational Amplifier

Figure 3. Two-Byte Command Sequence
SCL
X9438
SDA
S 0 1 0 1 A3 A2 A1 A0 A I3 I2 I1 I0 R1 R0 0 P0 A S
T
C
CT
A
K
KO
R
P
T
Figure 4. Three-Byte Command Sequence
SCL
SDA
S 0 1 0 1 A3 A2 A1 A0 A I3 I2 I1 I0 0 P0 R1 R0 A
T
C
C
A
K
K
R
T
D5 D4 D3 D2 D1 D0 A S
CT
KO
P
The Increment/Decrement command is different from
the other commands. Once the command is issued
and the X9438 has responded with an acknowledge,
the master can clock the selected wiper up and/or
down in one segment steps; thereby, providing a fine
tuning capability to the host. For each SCL clock pulse
(t_HIGH) while SDA is HIGH, the selected wiper will
move one resistor segment towards the V_H terminal.
Similarly, for each SCL clock pulse while SDA is LOW,
the selected wiper will move one resistor segment
towards the V_L terminal. A detailed illustration of the
sequence for this operation is shown in Figure 5.
Figure 5. Increment/Decrement Command Sequence
SCL
SDA
XX
S 0 1 0 1 A3 A2 A1 A0 A I3 I2 I1 I0 P1 P0 R1 R0 A I I
T
C
CN N
A
K
KCC
R
12
T
ID
NE
CC
n1
DS
ET
CO
nP
5
FN8199.0
March 11, 2005