Multisim 4-bit counter

Discussion in 'Homework Help' started by ttrianta, Feb 13, 2014.

  1. ttrianta

    Thread Starter New Member

    Feb 13, 2014
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    Hey everyone!

    As part of a project, I have to create a 4-bit counter and a BCD to 7-segment decoder, that takes the value produced by the counter and displays it on a LED. I have completed the circuit in Multisim, but the only value displayed on the LED is "1". I've been trying -unsuccesfully- for hours to solve the problem, but at this point I am pretty stack. I've attached the circuit for anyone who'd care to have a look and offer some assistance.
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,386
    496
    Have you checked the 4 bit counter? It sounds like it counts only one time, from 0 to 1, and then stops, so you only get 1 on the 7 segment display.
     
  3. ttrianta

    Thread Starter New Member

    Feb 13, 2014
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    I think it should work the way I've designed it and reset after going to 9. But it really doesn't seem to be functioning that way for some reason.
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
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    Try taking a screenshot of your schematic, otherwise, the only way to view your circuit it's with Multisim...
     
  5. ttrianta

    Thread Starter New Member

    Feb 13, 2014
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  6. absf

    Senior Member

    Dec 29, 2010
    1,492
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    Try remove R4 470Ω and see if it works.:rolleyes:

    I think the resistance is too low for the AND gate to pull its output high..

    Allen
     
    Last edited: Feb 13, 2014
  7. ttrianta

    Thread Starter New Member

    Feb 13, 2014
    5
    0
    Just tried removing the R4. Unfortunately, I only get "1" displayed still
     
  8. ttrianta

    Thread Starter New Member

    Feb 13, 2014
    5
    0
    Problem solved. Being really bad with physics, I had messed up the resistance and capacitor values of the 555. Here is a screenshot of it working properly for anyone interested.

    http://i60.tinypic.com/2rzqgb7.jpg
     
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