10

FN8183.1

September 9, 2005

The system may select the X9317, 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 memory; 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

MODE

L

H

Wiper up

L

L

Wiper down

H

X

Store wiper position to nonvolatile

memory

H

X

X

Standby

L

X

No store, return to standby

L

H

Wiper Up (not recommended)

L

L

Wiper Down (not recommended)

X9317