7

FN8222.3

July 20, 2009

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) a 7-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 non-volatile memory

whenever CS transitions HIGH while the INC input is also

HIGH.

The system may select the X9Cxxx, move the wiper and

deselect the device without having to store the latest wiper

position in non-volatile memory. After the wiper movement is

performed as previously described 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 power-down/up cycle

recalled the previously stored data.

This procedure allows the system to always power-up to a

pre-set value stored in non-volatile memory; then during

system operation, minor adjustments could be made. The

adjustments might be based on user preference, i.e.: 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.

Symbol Table

Performance Characteristics

Contact the factory for more information.

Applications Information

Electronic digitally controlled (XCDP) potentiometers provide

three powerful application advantages:

1. The variability and reliability of a solid-state

potentiometer.

2. The flexibility of computer-based digital controls.

3. The retentivity of non-volatile memory used for the

storage of multiple potentiometer settings or data.

Mode Selection

CS

INC

U/D

MODE

L

H

Wiper Up

L

L

Wiper Down

H

X

Store Wiper Position

H

X

X

Standby Current

L

X

No Store, Return to Standby

L

H

Wiper Up (not recommended)

L

L

Wiper Down (not recommended)

WAVEFORM

INPUTS

OUTPUTS

Must be

steady

Will be

steady

May change

from Low to

High

Will change

from Low to

High

May change

from High to

Low

Will change

from High to

Low

Don’t Care:

Changes

Allowed

Changing:

State Not

Known

N/A

Center Line

is High

Impedance

X9C102, X9C103, X9C104, X9C503