How To Understand Ex3 Sum Mechanism?

Discussion in 'Homework Help' started by transgalactic, May 7, 2008.

  1. transgalactic

    Thread Starter Active Member

    Apr 29, 2008
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    0
    i need to implement a circuit that inputs two 4bit numbers (y3 y2 y1 y0 x3 x2 x1 x0)
    and it has an output of (c3 c2 c1 c0 s3 s2 s1 s0) where "c" is the carry
    and "s" is the sum

    i was given an example in which X=0101 (5) Y=1000 (8) and it outputs
    S=1010 (10) and C=0011 (3)
    5+8=13

    i dont know what is the role of C and S
    how do they split the numbers???

    i was asked to implement it using two 4 bit adders

    here is the answer:
    http://s290.photobucket.com/albums/ll279/t...nt=IMG_8831.jpg

    i cant understand this circuit
    ????????
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    That makes two of us. Whadya gonna do?
     
  3. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    This four bit adder circuit... it accept binary input and provides BCD output?
     
  4. Papabravo

    Expert

    Feb 24, 2006
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    I think your example is wrong. It certainly makes no sense to me.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    Could it be doing excess 3 encoding?
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    If you line up X and Y there should be no carries.
     
  7. transgalactic

    Thread Starter Active Member

    Apr 29, 2008
    74
    0
    how can you explain that
    S binary column is bigger by 6 then DEC number
    and when the DEC number goes bigger then 10
    then it has "1" and a normal number
    the dec number is supposed to equal to the binay
    noy to be smaller by 6
    ???

    and in the EX3 column we each number is bigger by 3 then DEC number
    and when the DEC number is smaller then 10
    we dont have another 4 bits
    ?????????
     
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