Building a 2 bit grey code counter with a clr and inc input

Discussion in 'Homework Help' started by Kevin2341, Mar 25, 2014.

  1. Kevin2341

    Thread Starter Member

    Nov 1, 2009
    19
    0
    Hey everyone,

    I've been stumped on getting a certain digital circuit working as it needs to for my digital design class. The goal is this:

    "Design a 2-bit gray code counter with a CLR input and an INC input (using D Flip-flops). In cases where CLR = INC = '1', have the counter also increment. Draw a schematic of the resulting counter. Use the sequence 00 -> 01 -> 11 -> 10 -> 00 ...

    Here is the associated truth table, Karnaugh Maps, and logic equations I have derived so far...

    Capture.PNG

    Every attempt thus far at building this circuit has failed in the correct operation. I have a sneaking hutch that it is because the CLR input got completely removed from the equations, but I have triple checked my Kmaps and am fruitless.

    Can anyone help me get pointed in the right direction? Does it look like I did something obviously wrong?

    Here is the schematic I have built thus far (sorry it's horribly ugly, I built it quickly)

    cap2.PNG
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,039
    3,243
    Have you connected all the unused inputs to ground or V+ as appropriate?
     
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