Decade 4-bit Synchronous Counter using D flop flop (Divide-by-2 Counter)

Discussion in 'Homework Help' started by JohnTZ, Mar 30, 2015.

  1. JohnTZ

    Thread Starter New Member

    Mar 30, 2015
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    Decade 4-bit Synchronous Counter using D flop flop (Divide-by-2 Counter): Modify the following circuit so that it counts up from "0000" to "1000" and then resets. Use either AND, OR and Inverters or NAND gates.

    [​IMG]

    Any help is appreciate.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,140
    1,790
    That is not a synchronous counter. In a synchronous counter the same clock line would go to all four flip flops. What you have drawn is called a ripple counter and it takes a while for the counter to go from one stable state to another.
     
  3. JohnTZ

    Thread Starter New Member

    Mar 30, 2015
    4
    0
    Hello! Papabravo,

    Thanks for info, could you please help me what should I do to modify the circuit to let it count up only from '0000' to '1000' instead of count from '0000' to '1111'?

    Any hint is appreciate.
     
  4. MrChips

    Moderator

    Oct 2, 2009
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  5. tshuck

    Well-Known Member

    Oct 18, 2012
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    In addition to the thread MrChips linked to, I also wrote a thread on modulus counters, which you may find useful as it includes an example of designing a decade counter using JK flip flops. The approach is the same, but your input forming logic will change.
     
  6. Papabravo

    Expert

    Feb 24, 2006
    10,140
    1,790
    HINT: All your flip flops must be clocked by a common clock signal.
    HINT: Design a decoder for the state '1000'
    That's two hints before breakfast.
     
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