- 29th January 2005, 09:36 #1

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## How to make XOR gate using 2x1 multiplexer?

Hi

Is it possible to make XOR gate using 2x1 multiplexer?

if yes how? if no why?

- 29th January 2005, 09:48 #2

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## 2x1 mux using nand gates

Let me take a shot.

Below is the truth table of a 2x1 multiplexer.

A B S | O

======

0 0 0 | 0

0 0 1 | 0

0 1 0 | 0

0 1 1 | 1

1 0 0 | 1

1 0 1 | 0

1 1 0 | 1

1 1 1 | 1

I can't seem to find any combination of 2-inputs and one fixed-input giving an XOR gate.

- 29th January 2005, 09:48

- 29th January 2005, 10:26 #3

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## realize nand gate as xor gate

Well if you have more than 1 2x1 Multiplexer it can be done. If you have 2 2x1 Multiplexers you can make a NAND gate. And then by 4 Nand Gates you can make a XOR Gate.

2x1 to AND:

Tie A to 0, then the Mux is a AND Gate with Inputs B and S. Make an Inverter of the 2nd Mux by tying A, B to say 1, 0. And cascade the 2, you have a NAND. Use 4 such NANDs to get a XOR. Thus to make a XOR by this way u need 8 2x1 MUX !

Hope this helped !!

- 29th January 2005, 10:26

- 29th January 2005, 12:23 #4

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## using mux to make xor gate

Originally Posted by**aryajur**

First of all, you can build 4x1 MUX from those 3 2x1 MUXes. And then use the same approach as LUT in FPGA, by providing constant 1s and 0s on MUX inputs, that correspond to output column of truth table for desired gate.

- 29th January 2005, 12:23

- 31st January 2005, 07:45 #5

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## xor gate from 2 to 1 mux truth table

You can build any logic using 2x1 MUX. The only reason why we don't use that it will be not optimal design.

- 31st January 2005, 09:50 #6

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## build a +nand gate using a +multiplexer

Here it goes...

Code:+-----+ b ---|0 | | |---> Y = a xor b b_bar ---|1 S | +--+--+ | a------+

- 31st January 2005, 10:26 #7

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## how to make an xor gate with 2 muxes

Originally Posted by**Fom**

- 4th March 2007, 04:12 #8

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## xor by nand gate

With single 2*1 mux u may not get X-0r gate..........but by using more than 1 mux and by using additional gates u can realize x-or gate ..

- 5th March 2007, 04:27 #9

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## xor gate with two mux

Hi..

Yes It is Possible to make Xor gate using single 2:1 Mux.

Here is the way

Lets say inputs of xor gate are A and B and output=y

connect select line to A

Connect 0 -> B

and 1 -> B_bar

- 5th March 2007, 09:08 #10

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## xor by only nand gate

Originally Posted by**checkmate**

- 5th March 2007, 10:13 #11

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## xor gate from two mux

Hi,

You can design any logic using mux in two ways,using Levevls and/or using interconnection between differernt nodes.

For XOR implementation..interconnection without using Levels

(A)i0------!\

! !__Y

i1 !---! !

! !/

!__ !

!

!

(B)Sel

Refer www.asic-world.com for many VLSI stuff, it is a nice website by Deepak Kumar Tala ..Thanks Deepak

- 5th March 2007, 10:17 #12

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## ways to build an xor gate out of nand gates

Originally Posted by**nand_gates**

Added after 1 minutes:

Originally Posted by**mohammed.peer**