Question

Why the lower order address bus is multiplexed with data bus how they will be demultiplexed

Answer 1

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

Plzz mark as brainlist !!

Answer 2

Answer: The major rationale for multiplexing the address and data bus is to minimise the number of address and data pins and allocate those pins to other CPU operations. These multiplexed lines carried the lower order 8 bit address as well as the data bus.

Explanation:

Multiplexing is used to minimise the number of 8085 pins. External memory or I/O devices, on the other hand, require a distinct 16-bit address A15 - A0 for decoding and choosing a device, as well as a separate D7 - D0 for data transmission.

As a result, the multiplexed address-data bus must be demultiplexed such that memory and I/O devices have their own address A15 - A0 and data bus D7 - D0. Demultiplexing can be accomplished with the aid of the ALE signal (Address Latch Enable) generated by the CPU. On the 8085 microprocessor, the data bus and the low order address bus are multiplexed. This enables for the utilisation of 8 pins instead of the usual 16.

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