3

FN8205.1

September 6, 2005

PIN DESCRIPTIONS

The high (VH/RH) and low (VL/RL) terminals of the

X9511 are equivalent to the fixed terminals of a

mechanical potentiometer. The minimum voltage is -5V

and the maximum is +5V. It should be noted that the

terminology of VL/RL and VH/RH reference the relative

position of the terminal in relation to wiper movement

direction selected by the PU and PD inputs, and not the

voltage potential on the terminal.

PU

The debounced PU input is for incrementing the wiper

position. An on-chip pull-up holds the PU input HIGH.

A switch closure to ground or a LOW logic level will,

after a debounce time, move the wiper to the next

adjacent higher tap position.

PD

The debounced PD input is for decrementing the wiper

position. An on-chip pull-up holds the PD input HIGH.

A switch closure to ground or a LOW logic level will,

after a debounce time, move the wiper to the next

adjacent lower tap position.

ASE

The debounced ASE (AUTOSTORE enable) pin can

be in one of two states:

down, an automatic store cycle takes place.

initiate a manual store operation. This is for the user

who wishes to connect a push button switch to this pin.

For every valid push, the X9511 will store the current

wiper position to the EEPROM.

PIN CONFIGURATION

PIN NAMES

DEVICE OPERATION

There are three sections of the X9511: the input control,

counter and decode section; the EEPROM memory;

and the resistor array. The input control section oper-

ates just like an up/down counter. The output of this

counter is decoded to turn on a single electronic switch,

connecting a point on the resistor array to the wiper out-

put. Under the proper conditions the contents of the

counter can be stored in EEPROM memory and

retained for future use. The resistor array is comprised

of 31 individual resistors connected in series. At either

end of the array and between each resistor is an elec-

tronic switch that transfers the potential at that point to

the wiper.

The X9511 is designed to interface directly to two

push button switches for effectively moving the wiper

up or down. The PU and PD inputs increment or dec-

rement a 5-bit counter respectively. The output of this

counter is decoded to select one of the thirty-two wiper

positions along the resistive array. The wiper incre-

ment input, PU and the wiper decrement input, PD are

both connected to an internal pull-up so that they nor-

mally remain HIGH. When pulled LOW by an external

push button switch or a logic LOW level input, the

wiper will be switched to the next adjacent tap posi-

tion.

Internal

debounce

circuitry

prevents

inadvertent

switching of the wiper position if PU or PD remain

LOW for less than 40ms, typical. Each of the buttons

can be pushed either once for a single increment/dec-

rement or continuously for a multiple increments/dec-

rements. The number of increments/decrements of the

wiper position depend on how long the button is being

pushed. When making a continuous push, after the

first

second,

the

increment/decrement

speed

increases. For the first second the device will be in the

slow scan mode. Then if the button is held for longer

than 1 second the device will go into the fast scan

mode. As soon as the button is released the X9511

will return to a standby condition.

PU

PD

1

2

3

4

8

7

6

5

X9511

DIP/SOIC

ASE

Symbol

Description

High Terminal

Wiper Terminal

Low Terminal

Ground

Supply Voltage

PU

Push Up Input

PD

Push Down Input

ASE

AUTOSTORE Enable Input

X9511