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Synchronous 3-bit up/down counter

  1. May 23, 2012 #1
    1. The problem statement, all variables and given/known data

    Design and implement a synchronous 3-bit up/down counter with the following decimal code sequence: 0,1,3,5,7,6,4,2,0,… The counter should count “up” when an UP/DOWN control input Y is 1, and count “down” when the control input is 0.

    • Counting “up”
      decimal: 0,1,3,5,7,6,4,2,0,…
      binary: 000,001,011,101,111,110,100,010,000,…
    • Counting “down”
      decimal: 0,2,4,6,7,5,3,1,0,…
      binary: 000,010,100,110,111,101,011,001,000,…

    2. The attempt at a solution

    I don't know if the state diagram and Table are right but im having trouble with the flip-flop transition table and the simplified logic expressions for flip-flop inputs. could someone help me out please

    imageshack.us/f/822/statediagram2.png/

    Picture of state diagrams and state table
     
  2. jcsd
  3. May 23, 2012 #2
    imageshack.us/f/822/statediagram2.png/

    Picture of state diagrams and state table
     
  4. May 24, 2012 #3
    Please can anyone help me i have built the circuit in logisim but its not counting to what it was suppose to

    its counting 0,4,5,7,6,2,3,0

    instead of 0,1,3,5,7,6,4,2,0
     
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