Question

What is the advantage of multiplexing of address bus over data bus in 8085?

Answer 1

Introduction

The Main Concern In Digital Electronics is to Reduce the space required for building the electronic Chip.Reduction Of space means reduction of cost and building a efficient electronic circuits.

8085:

The main reason of multiplexing address and data bus is to reduce the number of pins for address and data and dedicate those pins for other several functions of microprocessor.

These multiplexed set of lines used to carry the lower order 8 bit address as well as data bus.

Justification:

So how Does It Reduces Number Of Pins?

Can be understood with help of Multiplexer

(MUX 2:1)-That is 2Inputs 1 Output

Multiplexer Combines Many Signals to One Signal

So Here 1st Input is Address A0-A7 and second input is Data D0-D7

And with help of selector Line(ALE Pin) I can use one at a time

For Example ALE =0 Data is Selected

ALE =1 Address is Selected

Hence with help of multiplexing we reduce from 16 pins to 8pins