X9319 Datasheet, PDF (7/10 Pages) Xicor Inc. – Digitally Controlled Potentiometer (XDCP)

X9319
INSTRUCTIONS AND PROGRAMMING
The INC, U/D and CS inputs control the movement of
the wiper along the resistor array. With CS set LOW the
device is selected and enabled to respond to the U/D
and INC inputs. HIGH to LOW transitions on INC will
increment or decrement (depending on the state of the
U/D input) the seven bit counter. The output of this
counter is decoded to select one of one hundred wiper
positions along the resistive array.
The value of the counter is stored in nonvolatile mem-
ory whenever CS transitions HIGH while the INC input
is also HIGH.
The system may select the X9319, move the wiper and
deselect the device without having to store the latest
wiper position in nonvolatile memory. After the wiper
movement is performed as described above and once
the new position is reached, the system must keep INC
LOW while taking CS HIGH. The new wiper position
will be maintained until changed by the system or until
a powerup/down cycle recalled the previously stored
data. This procedure allows the system to always
power-up to a preset value stored in nonvolatile mem-
ory; then during system operation minor adjustments
could be made. The adjustments might be based on
user preference, system parameter changes due to
temperature drift, etc.
The state of U/D may be changed while CS remains
LOW. This allows the host system to enable the device
and then move the wiper up and down until the proper
trim is attained.
MODE SELECTION
CS INC U/D
L
H
L
L
H
X
H
X
X
L
X
L
H
L
L
Mode
Wiper up
Wiper down
Store wiper position to
nonvolatile memory
Standby
No store, return to standby
Wiper Up (not recommended)
Wiper Down
(not recommended)
REV 1.7 7/10/03
www.xicor.com
7 of 10