counter question

Discussion in 'Homework Help' started by hazim, Jan 23, 2008.

  1. hazim

    Thread Starter Active Member

    Jan 3, 2008
    419
    13
    hi
    in any counter; for example the one i'm building, a 0-15 counter; how do i make this counter reachs a certain number and stops and then this number stays displayed by the 7-segment display...my aim is to let the counter count from 0 till 15 and then the counter stops at 15 where the 7-segment displays 15...any help?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    282
    In order for 7 segment displays to show the two digit value of 15, you will need two displays. With external logic, a single binary counter will do, but it might be easier with two decimal counters.

    Are you using standard logic for the counter, or are you doing an exercise to make a discreet design?
     
  3. hazim

    Thread Starter Active Member

    Jan 3, 2008
    419
    13
    i'm doing a project and my instructor needs me to work and design by myself....i designed an external circuit to obtain two digits on two 7 segment displays from the 7493 binary counter....
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    Then you will want some external logic to stop the clock when the count is 15.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Hmm - since this is "homework", shouldn't it be in the "homework" section?
     
  6. hazim

    Thread Starter Active Member

    Jan 3, 2008
    419
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    maybe you are right SgtWookie...it's a final course project. i'am asking about the concept of this external circuit beenthere
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    Think of a logic gate that would change its output when the counter state went to 15 and whose output would disable another gate from passing any further clock pulses.
     
  8. luck

    New Member

    Jan 25, 2008
    8
    0
    you can use a latch that triggers before the display such that when the MSB would go from high to low you lock the 15 value in the display; you can also use this latch to stop the clock/input source for good measure.
     
  9. hazim

    Thread Starter Active Member

    Jan 3, 2008
    419
    13
    I used AND gates to get 1 when the counter reaches 15, and then i connected this 1 with the clock signal to the inputs of a NOR gate and i connected this final output from the NOR gate to the clk input of the counter....It's solved now.thanks.
     
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