X9410_06 Datasheet, PDF (6/21 Pages) Intersil Corporation – Dual Digitally Controlled Potentiometer

X9410
Five instructions require a three-byte sequence to
complete. These instructions transfer data between the
host and the X9410; either between the host and one of
the data registers or directly between the host and the
Wiper Counter Register. These instructions are:
– Read Wiper Counter Register—read the current
wiper position of the selected pot,
– Write Wiper Counter Register—change current
wiper position of the selected pot,
– Read Data Register—read the contents of the
selected data register;
– Write Data Register—write a new value to the
selected data register.
– Read Status—This command returns the contents
of the WIP bit which indicates if the internal write
cycle is in progress.
Figure 4. Two-Byte Instruction Sequence
The sequence of these operations is shown in Figure 5
and Figure 6.
The final command is Increment/Decrement. It is
different from the other commands because it’s length
is indeterminate. Once the command is issued, the
master can clock the selected wiper up and/or down in
one resistor segment steps, thereby providing a fine
tuning capability to the host. For each SCK clock pulse
(t_HIGH) while SI is HIGH, the selected wiper will move
one resistor segment towards the V_H/R_H terminal.
Similarly, for each SCK clock pulse while SI is LOW,
the selected wiper will move one resistor segment
towards the V_L/R_L terminal. A detailed illustration of the
sequence and timing for this operation are shown in
Figure 7 and Figure 8.
CS
SCK
SI
0 1 0 1 0 0 A1 A0 I3 I2 I1 I0 R1 R0 0 P0
Figure 5. Three-Byte Instruction Sequence (Write)
CS
SCL
SI
0 1 0 1 0 0 A1 A0
I3 I2 I1 I0 R1 R0 0 P0
Figure 6. Three-Byte Instruction Sequence (Read)
0 0 D5 D4 D3 D2 D1 D0
CS
SCL
SI
0 1 0 1 0 0 A1 A0
I3 I2 I1 I0 R1 R0 0 P0
S0
Don’t Care
0 0 D5 D4 D3 D2 D1 D0
6
FN8193.2
October 12, 2006