All About Circuits Forum Implement function with 4:1 & 2:1 Multiplexers
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#1
11-13-2010, 07:56 PM
 tquiva Senior Member Join Date: Oct 2010 Posts: 176
Implement function with 4:1 & 2:1 Multiplexers

I'm trying to implement four functions using a minimum number of 2:1 and 4:1 muxes with NO additional gates.

This is my truth table:

Right now, I'm currently working on function Z.
I grouped the rows into pairs accordingly:

When ABC=000, Z = D
When ABC=001, Z = D
When ABC=010, Z = D
When ABC=011, Z = D

When ABC=100, Z = D'
When ABC=101, Z = D'
When ABC=110, Z = D'
When ABC=111, Z = D'

So therefore I would need a mux with 8 data inputs?
I put two 4:1 muxes together, with the select inputs labeled with A, B, C
And I just labeled the data inputs by D.H (high), or D.L (low) according to the pairs above

This is what I have so far for function Z.
I really don't know how to label the pins or make the connections to connect both muxes together. Could someone please help me on this?

Edit:
I edited the above circuit to this one. But I still don't know how to cascade several muxes. I don't know where to connect the select inputs and other connections. Could someone please help me asap?

Last edited by tquiva; 11-14-2010 at 12:02 AM.
#2
11-14-2010, 12:40 AM
 mik3 Senior Member Join Date: Feb 2008 Location: Cyprus, but now in UK (GMT+0) Posts: 4,846 Blog Entries: 9

Connect B and C inputs to S1 and S0 of both multiplexers respectively. Use A input to select which multiplexer is active. When A=0, the top multiplexer shall be active (connect to A via NOT gate) and when A=1 the bottom multiplexer shall be active (connect directly to A). However, you don't need these multiplexers to achieve that. Z=D when A=0 and Z=D' when A=1, thus a simple logic circuit can achieve this.
 The Following User Says Thank You to mik3 For This Useful Post: tquiva (11-14-2010)
#3
11-14-2010, 04:16 AM
 tquiva Senior Member Join Date: Oct 2010 Posts: 176

thank you!

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