[Urgent] Design a counter with using D Flip-Flop

Discussion in 'Homework Help' started by Astrokit, Mar 18, 2009.

  1. Astrokit

    Astrokit Thread Starter New Member

    Joined:
    Mar 18, 2009
    Messages:
    1
    The question is :
    Design a counter that counts pulses on line w and displays the count in the sequence 0,2,1,3,0,2, ... Use D Flip-Flops in your circuit.

    i wanna ask how to design this circuit?
    What are the steps to design this circuit?
    and What is the answer of this question?

    the ans. of the expressions are D(input) of A = A XOR B and D(input) of B = not A??

    thank a lot~ =]
  2. Papabravo

    Papabravo AAC Fanatic!

    Joined:
    Feb 24, 2006
    Messages:
    5,855
    Location:
    Michigan, USA (GMT-5)
    Write a Truth Table
    Code:
     A  B  |  P  Q
    ---------------
     0  0  |  1  0
     0  1  |  1  1
     1  0  |  0  1
     1  1  |  0  0
    
    Columns A and B represent the current Q-output state of each of the D-Flip-Flops
    Columns P and Q represent the next Q-output state of D-Flip-Flops A and B respectively.
    When you present the next Q-output state on the D-inputs, the sequence of states is:
    Code:
    0 -> 2 -> 1 -> 3 -> 0 ...
    
    By inspection:
    Code:
    P = .NOT. A   
    Q = A .XOR. B = (A .AND. .NOT. B) .OR. (.NOT. A .AND. B)
    
    P and Q could, of course, be any functions of two boolean variables, and the sequences would change accordingly.
    [Question] What sequence do you get if you swap the functions for P and Q?

    It's not rocket science after all, just boolean algebra.
  3. wr8y

    wr8y Active Member

    Joined:
    Sep 16, 2008
    Messages:
    232
    Location:
    Griffin, GA USA
    That Boolean guy was WAY ahead of his time. :cool:

    But I still think Boolean Algebra is weird stuff.
  4. Papabravo

    Papabravo AAC Fanatic!

    Joined:
    Feb 24, 2006
    Messages:
    5,855
    Location:
    Michigan, USA (GMT-5)
    That's George Boole,

    http://en.wikipedia.org/wiki/George_Boole

    and I think Tensor Algebra, Riemanian Manifolds, Fractal Geometry, and Stochastic Calculus are way more wierd and complicated. Just my opinion -- I could be wrong.

    http://en.wikipedia.org/wiki/Tensor_algebra
    http://en.wikipedia.org/wiki/Riemannian_manifold
    http://en.wikipedia.org/wiki/Fractal
    http://en.wikipedia.org/wiki/Stochastic_calculus
    Last edited: Mar 18, 2009
Similar Threads
Forum Title Date
Homework Help [Urgent] Homework help (DC Circuits) Mar 24, 2011
Homework Help I Hate My Logic Design Class... Today at 1:48 AM
Homework Help How Do I Design A Mod 6 Counter Without The Use Of Logic Gate? Aug 30, 2014
Homework Help D Flip-Flops: Design a counting circuit Jul 14, 2014
Homework Help [help] Designing am transmitter Jul 11, 2014

Share This Page