X9409 Datasheet, PDF (5/21 Pages) Xicor Inc. – Quad Digitally Controlled Potentiometers

X9409 – Preliminary Information
Figure 3. Two-Byte Instruction Sequence
SCL
SDA
S 0 1 0 1 A3 A2 A1 A0 A I3 I2 I1 I0 R1 R0 P1 P0 A S
T
C
CT
A
K
KO
R
P
T
The Increment/Decrement command is different from
the other commands. Once the command is issued and
the X9409 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/R_H terminal. Similarly,
for each SCL clock pulse while SDA 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
Figures 5 and 6 respectively.
Table 1. Instruction Set
Instruction Set
Instruction
I₃ I₂ I₁ I₀ R₁ R₀ P₁ P₀
Operation
Read Wiper Counter
Register
1 0 0 1 0 0 P₁ P₀ Read the contents of the Wiper Counter
Register pointed to by P₁–P₀
Write Wiper Counter
Register
1 0 1 0 0 0 P₁ P₀ Write new value to the Wiper Counter Register
pointed to by P₁–P₀
Read Data Register
1 0 1 1 R₁ R₀ P₁ P₀ Read the contents of the Data Register pointed
to by P₁–P₀ and R₁–R₀
Write Data Register
1 1 0 0 R₁ R₀ P₁ P₀ Write new value to the Data Register pointed to
by P₁–P₀ and R₁–R₀
XFR Data Register to 1 1 0 1 R₁ R₀ P₁ P₀ Transfer the contents of the Data Register
Wiper Counter Register
pointed to by P₁–P₀ and R₁–R₀ to its associated
Wiper Counter Register
XFR Wiper Counter
Register to Data
Register
Global XFR Data
Registers to Wiper
Counter Registers
1 1 1 0 R₁ R₀ P₁ P₀ Transfer the contents of the Wiper Counter
Register pointed to by P₁–P₀ to the Data
Register pointed to by R₁–R₀
0 0 0 1 R₁ R₀ 0
0 Transfer the contents of the Data Registers
pointed to by R₁–R₀ of all four pots to their
respective Wiper Counter Registers
Global XFR Wiper
Counter Registers to
1 0 0 0 R₁ R₀ 0
0 Transfer the contents of both Wiper Counter
Registers to their respective Data Registers
Data Register
pointed to by R₁–R₀ of all four pots
Increment/Decrement 0 0 1 0 0 0 P₁ P₀ Enable Increment/decrement of the WCR Latch
Wiper Counter Register
pointed to by P₁–P₀
Note: (7) 1/0 = data is one or zero
REV 1.6 1/30/03
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Characteristics subject to change without notice. 5 of 21