2

FN6126.0

August 22, 2005

Block Diagram

7-BIT

UP/DOWN

COUNTER

RECALL

CONTROL

CIRCUITRY

ONE

OF

128

DECODER

RESISTOR

ARRAY

U/D

INC

CS

TRANSFER

GATES

INTERFACE

UP/DOWN

(U/D)

INCREMENT

(INC)

DEVICE SELECT

(CS)

V-

GND

SIMPLE BLOCK DIAGRAM

DETAILED BLOCK DIAGRAM

0

1

2

124

125

126

127

AND

CONTROL

Pin Descriptions

PIN NUMBER

SYMBOL

DESCRIPTION

1U/D

Controls the direction of wiper movement and whether the counter is incremented or decremented.

2

V-

Negative supply voltage for the potentiometer wiper control.

3

GND

Ground. Should be connected to a digital ground.

4CS

Chip Select. The device is selected when the CS input is LOW.

5

NC

No Connect. Pin is to be left unconnected.

6RH

A fixed terminal for one end of the potentiometer resistor.

7RW

The wiper terminal which is equivalent to the movable terminal of a potentiometer.

8RL

A fixed terminal for one end of the potentiometer resistor.

9

VCC

Positive logic supply voltage.

10

INC

Increment input; negative edge triggered.

ISL23710