School Project Help!

Discussion in 'Homework Help' started by Transon, Nov 4, 2013.

  1. Transon

    Thread Starter New Member

    Nov 4, 2013
    1
    0
    Okay, I've recently began to study electronics on school and tomorrow I got a BIG test, and I need big help because I cant seem to understand how I start the circuit.

    Its a Binary counter with 4 JK-Flip Flops, and they're inverted at the start as you can see.

    http://vvcap.net/db/gR-BVk0KYT9jQ1cZsG06.htp

    Here is the whole circuit.

    http://vvcap.net/db/PBXZ0e2u_mXxmNGvOrP4.htp

    This is the one I'm not sure of, how am I supposed to make those "switches" with 0 and 1.

    http://vvcap.net/db/GO9_7FQ6F_5X8wMZclo-.htp
    Image of the task.

    Please give me some tips :)
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,764
    2,534
    It looks OK to me. I'm not sure what the question is. Generally it is assumed (and you have the set/reset lines wired to make it so) that a counter starts on 0000.

    These flip flops toggle on the negative edge, so as the previous number goes to zero the next digit goes to a one.

    I used to bread board those circuits for fun when I started out, over 40 <mumble> years ago.
     
    Transon likes this.
  3. vini_i

    New Member

    Apr 19, 2010
    14
    1
    some flip flops have a set and reset built into them. the two switches that you mention are to set (store a one) or reset (store a zero) in the flip flop regardless of what is at the input.

    when a flip flop first powers up the state that is stored in it is unpredictable. it can be a zero or one. so the set and reset functions are used to change the state of all the flip flops to a particular value so that everything else is predictable.

    this is generally invoked by some device that can sense a power up condition and change the state of all the flip flops to a set state.

    or in this case to reset the counter to either all zeros or all ones.
     
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