1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Having trouble forming an equation on 2 bit subtractor

  1. Jan 19, 2017 #1
    1. The problem statement, all variables and given/known data
    We are asked to make a subtractor circuit which has a 2 bit, 2 input data.

    2. Relevant equations

    A1A0

    _

    B1B0

    _________________________________


    3. The attempt at a solution

    I would have a 3 bit output with one borrow. The problem is I am stuck at this point and am having troubles forming an equation. Someone lent me their diagram and this is what I have

    PeivRyS.png



    I have tried building this on the breadboard but it gives off an erroneous result at the 7 segment cathode with the ls48 decoder for the 4th time I assembled this. It only gives off 0 and 4 at the LED matrix when it should be 3,2,1,0. The upper LED is the rightmost bit while the third led is the third bit
     
  2. jcsd
  3. Jan 19, 2017 #2

    berkeman

    User Avatar

    Staff: Mentor

    Can you show us the truth table for the subtractor? And the K-maps that correspond to each of the outputs?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Having trouble forming an equation on 2 bit subtractor
  1. Having trouble with c (Replies: 2)

Loading...