X9410_06 Datasheet, PDF (4/21 Pages) Intersil Corporation – Dual Digitally Controlled Potentiometer

X9410
Wiper Counter Register (WCR)
The X9410 contains two Wiper Counter Registers, one
for each XDCP potentiometer. The WCR is equivalent
to a serial-in, parallel-out register/counter with its
outputs decoded to select one of sixty-four switches
along its resistor array. The contents of the WCR can
be altered in four ways: it may be written directly by the
host via the Write Wiper Counter Register instruction
(serial load); it may be written indirectly by transferring
the contents of one of four associated Data Registers
via the XFR Data Register or Global XFR Data Register
instructions (parallel load); it can be modified one step
at a time by the Increment/ Decrement instruction.
Finally, it is loaded with the contents of its Data Register
zero (DR0) upon power-up.
The Wiper Counter Register is a volatile register; that
is, its contents are lost when the X9410 is powered-
down. Although the register is automatically loaded
with the value in DR0 upon power-up, this may be
different from the value present at power-down.
Figure 1. Detailed Potentiometer Block Diagram
(One of Two Arrays)
Data Registers
Each potentiometer has four 6-bit nonvolatile Data
Registers. These can be read or written directly by the
host. Data can also be transferred between any of the
four Data Registers and the associated Wiper Counter
Register. All operations changing data in one of the
Data Registers is a nonvolatile operation and will take
a maximum of 10ms.
If the application does not require storage of multiple
settings for the potentiometer, the Data Registers can
be used as regular memory locations for system
parameters or user preference data.
Data Register Detail
(MSB)
(LSB)
D5
D4
D3
D2
D1
D0
NV
NV
NV
NV
NV
NV
Serial Data Path
From Interface
Circuitry
Register 0
8
Register 2
If WCR = 00[H] then V_W/R_W = V_L/R_L
If WCR = 3F[H] then V_W/R_W = V_H/R_H
Serial
Bus
Input
C
Register 1
o
u
6
Parallel
Bus
Input
n
t
e
r
Register 3
Wiper
Counter
D
Register
e
(WCR)
c
o
d
e
UP/DN
INC/DEC
Logic
UP/DN
Modified SCL
CLK
V_H/R_H
V_L/R_L
V_W/R_W
4
FN8193.2
October 12, 2006