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BCD Counter

Discussion in 'Electronic Basics' started by [email protected], Apr 27, 2006.

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  1. Guest

    After getting flamed for not cross posting last time, Ive learned the
    error of my ways.

    With some great help, I was able to build the complete circuit.

    I just had to connect two seven segment displays to it and make it able
    to count up to 99.

    I did that but I havent uploaded it as it doesnt look neat and would be
    a pain to look at.

    Now, during play the counter counts up at a regular pace. Then if I
    press stop it resets or if I press pause it stops the counter.

    The thing I cant seem to get is how to get Fast Forward to work. I need
    to make the counter go faster and have been unable to do that.

    The counter counts up using a bcd decade counter. As mentioned it
    counts fine, but I cant seem to figure out how to make it go faster.

    [img=http://img176.imageshack.us/img176/7059/compeng0tm.th.jpg]
     
  2. Guest

    sorry... I wasnt able to post the image correctly.

    You can simply click on on of the urls to view what I have done so far
     
  3. Ken Taylor

    Ken Taylor Guest

    I don't know what circuit you're using for your clock display, but if
    you use the fast forward output from the circuit you've linked to you
    can use it to gate either 'normal' speed clock pulses to your display
    circuit or higher-speed clock pulses (from further up the divider chain).

    Ken
     
  4. Guest

    Ive uploaded the image of the clock display now.

    http://img146.imageshack.us/my.php?image=untitled9sy.jpg

    Right now it counts up automatically to 9 and then resets.
     
  5. Ken Taylor

    Ken Taylor Guest

    Where are you getting your clock from? Use the fast forward signal to
    select a higher clock speed.

    Ken
     
  6. Guest

    the clock (squiggly line) is just there to represent where the input
    would come from.

    How do I select a higher clock speed ?
     
  7. Luhan

    Luhan Guest

    This is a mental exercise, no one would use this kind of circuit today.
    So just insert a binary divider and specify a faster clock. Then
    select the raw clock or the output of the divider.

    I once had to repair a TEAC reel to reel tape deck with logic like this
    using about a dozen relays. After attempting to trace the logic
    problem for some time, I concluded that the circuit was not defective,
    but that the signal simply got lost trying to find its way thru it...
    :)

    Luhan Monat (luhanxmonat-at-yahoo^dot^com)
    http://members.cox.net/berniekm/
    "Reality: what a concept!"
     
  8. JLU_EE

    JLU_EE Guest

    I agree with Luhan.
    But it is interesting.
     
  9. JLU_EE

    JLU_EE Guest

    I agree with Luhan.
    But it is interesting.
     
  10. DaveM

    DaveM Guest


    Just a few observations about your circuit.
    You don't show any pullup or pulldown resistors on the gate and flipflop inputs.
    Are you using any?
    What technology are you using for your ICs (TTL/LSTTL/CMOS, etc.)?
    I recommend pullup resistors on every input that might float while any of the
    switches are not being pushed. Floating inputs can cause all kinds of grief.

    The fast-forward circuit needs a faster clock than the normal speed counter
    circuit. Find a faster clock source for that counter.

    --
    Dave M
    MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
    address)

    They call it PMS because Mad Cow Disease was already taken.
     
  11. John Fields

    John Fields Guest

     
  12. Guest

    sry for my noobness, but I dont know how to access
    alt.binaries.schematics.electronic
     
  13. John Fields

    John Fields Guest

     
  14. Rich Grise

    Rich Grise Guest

    It's not noobness - it's from posting at googlegroups. (BTW, it's worth
    noting that you _do_ quote context, and you _do_ bottom-post - these are
    _good_ things. :) )

    But, as John said, get a real news server - ask your ISP, they probably
    already have one, and will be happy to teach you to access it.

    Good Luck!
    Rich
     
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