Mod-10 Counter

Discussion in 'Homework Help' started by num4ir, May 4, 2009.

  1. num4ir

    Thread Starter New Member

    May 4, 2009
    3
    0
    Hi, thanks for reading.
    I'm trying to construct a mod-10 counter but im stumbled, i did the best i can do but im afraid im missing or gates to make it a mod-10 im completely stumbled. I'm using t-ff's I'd appreciate it if someone could help me out
     
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  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    One way to get a modulo-10 counter is to watch the state of the flip-flops with external logic, so the next clock after the count of 9 sets the counter state back to 0.

    Another is like the 7490, with a divide by 2 stage, and three flip-flops that short count back to 0 after reaching 5.
     
  3. num4ir

    Thread Starter New Member

    May 4, 2009
    3
    0
    i'm not the brightest in this situation i appreciate the post but i still dont understand how to turn this mod-16 into a mod 10...i understand it counts to 0-15 which is 1111..i dont know
     
  4. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    what beenthere suggested first was simply look when the mod-16 counter gets to the number 9, or 1001, and then force the counter to go back to 0000. You have a RESET pin on each of your FF that will change the output to zero, most likely at the next clock.

    0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 0000, ....

    What logic can be used to detect the single state equal to 9?
     
  5. num4ir

    Thread Starter New Member

    May 4, 2009
    3
    0
    add an OR gate to fix q3 and q1?
     
  6. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    Why do you say q1 and q3? How about q0 and q3?

    Also, if you use an OR then anytime a 1 get placed in the output of either position you are looking at a RESET would be triggered. You want both conditions to be true, AND.
     
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