3 bit Synchronous Up Down Counter that automatically counts up and down

Discussion in 'Homework Help' started by rkobasketball, Mar 13, 2010.

  1. rkobasketball

    rkobasketball Thread Starter New Member

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    Hello everyone,
    I am in need of some extra help
    I have made an UP/DOWN binary synchronous counter that works with a switch that has a logic 1 for up counting and a logic 0 for down counting. The next part of this assignment is to make the counter switch from up to down automatically. This means that it will count
    0, 1, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2... (all in binary of course).:confused:
    I am 95% sure that I am going to need another J-K Flip Flop (74112) and at least 2 AND or NAND gates. If you do not feel like telling me all the information, just tell me what extra gates/inverters/flip-flops I need.
    Thanks so much in advance!
    -Julian Molina-Goni
  2. beenthere

    beenthere Retired Moderator

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    Take a look at a 74190 up/down counter.
  3. rkobasketball

    rkobasketball Thread Starter New Member

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    Sorry for not being specific, I can only use 74112, LS08, LS32, LS04, and maybe some NAND gates
    Nothing else
    hope this helps
    -Julian Molina-Goni
  4. k7elp60

    k7elp60 Active Member

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    You may want to look at the 4510 or the 4516 CMOS counters. They are 4 bit but they can preset to divide by 8. They have carry in and carry out terminals and the up/down count is by logic level on the U/D terminal. All these features may make it easier to do what you want.
  5. rkobasketball

    rkobasketball Thread Starter New Member

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    I am a high school junior, so I don't grasp full knowledge of CMOS and all of that.
    I can only use +5v chips and I am not sure about the difference between CMOS TTL etc.
    :confused:
  6. beenthere

    beenthere Retired Moderator

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    You can get the data sheet for a 74190 and look at the internal logic to see how to arrange a counter to do up/down counting and so on.
  7. BMorse

    BMorse Senior Member

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