Im trying to figure out how to make a 1 bit adder from a 4:1 mux 54ls153. I understand from what people say that if you can make the truth table you can figure it out but that's where im stuck at. I have the truth table but just can't figure out how to impliment it. Appreciante any help you can offer

truth table

x y cin sum carry
0 0 0 0 0
0 0 1 1 0
0 1 0 1 1
0 1 1 0 1
1 0 0 1 0
1 0 1 0 1
1 1 0 0 1
1 1 1 1 1

 

taken from a previous post with the same question

Let's have a quick review.

A one-bit adder has 2 input bits and one result bit. The two input bits represent one of four possible conditions.

A 4:1 multiplexer has four inputs and one output and TWO select bits. The two select bits select one of four possible constants (either 0 or 1) which can be routed to the output.

Are you starting to get the idea?

its been a while since ive done digital systems sorry i couldnt answer it , but at least i found the answer on the forums for you =]

 

Yeah i found that one and i don't know if im just being dumb or something but im having trouble grasping that

 

Arrange the inputs so the selection by the X & Y bits matches the desired condition from the truth table.

 

cool i figured out problem. I was basically thinking too hard into it. I was looking at the inside of mux trying to figure out how to get it to do what i want. So it's not so much that it is an adder but that you bacially give it cases and what to push to output for each case.

 

Yep, it's just a truth table selector.