3 bit down counter

Discussion in 'Homework Help' started by chillyster, Jan 30, 2012.

  1. chillyster

    Thread Starter New Member

    Jan 30, 2012
    2
    0
    can anyone help me design a 3-bit down counter that counts from 7 to 0? and when the counter reaches 0 an Led should light up to indicate that it reached 0. The inputs consist of Start/Stop pulse switch, a Preset pulse switch and a Clock Input. The output should be connected to the LEDs.
     
  2. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
  3. chillyster

    Thread Starter New Member

    Jan 30, 2012
    2
    0
    damn i dun understnd :(
     
  4. holnis

    Member

    Nov 25, 2011
    50
    4
    I believe there is enough informations in the links above. Anyway Counting down rather than up simply requires cascading the clocks using the inverted outputs.
    Check the attached description, it's an MOD-8 asynchronous down counter that counts from 7 to 0:
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,415
    3,354
    You can use an off-the-shelf down-counter or you can build it with flip-flops using Karnaugh maps.
     
Loading...