# MUX assignment question

Discussion in 'Homework Help' started by en1gma, Feb 22, 2013.

1. ### en1gma Thread Starter New Member

Feb 6, 2013
19
0
hello all,

for the assignment we are required to create a 4-1 mux using ONLY tri-state buffers. I have attatched my current diagram... I am new to circuits and would like to know how to verify my circuit is working correctly. We are using logicworks 5.

some additional notes about the assignment:

a. This MUX should have two selector lines S0 and S1 and four input lines A-D.
b. The output should match the following table:
S1 S0 || OUTPUT
0 0 || A
0 1 || B
1 0 || C
1 1 || D
In other words, when S0 and S1 are both zero the MUX will select input A for use as the output.

THANKS!

2. ### en1gma Thread Starter New Member

Feb 6, 2013
19
0
here is the diagram ... I believe, or hope, my logic is correct, but as I said, how can i test it in logic works5?

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3. ### WBahn Moderator

Mar 31, 2012
17,757
4,800
I don't see how it can be done. Consider the case in which both of your select lines are 0. How can you turn on ANY of the tri-state buffers?

4. ### WBahn Moderator

Mar 31, 2012
17,757
4,800
You are using things other than tri-state buffers, which violates the constraint you had capitalized in your first post.

So which is it? What are the design constraints?

5. ### en1gma Thread Starter New Member

Feb 6, 2013
19
0
My mistake, we can use tri-state buffers and inverters as well. Here is the full problem statement.

1. Create a 4-1 MUX using ONLY tri-state buffers and inverters in LogicWorks. This circuit will select one output from four inputs based on two addition switches. Please read textbook page 131 section 3-9 Multiplexers before implementing this lab assignment. You can test out your circuit using binary switches and a Hex keyboard

Hope this clears the confusion. Thanks again!

6. ### WBahn Moderator

Mar 31, 2012
17,757
4,800
In that case, your circuit looks fine. As for testing it in Logicworks 5, I have no idea -- I've never used it. Good luck.