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I have the following Karnaugh map's for JK flip flops. I've attempted to minimize them myself, however whenever I go to implement them I run in to an error. Anyone able to see if I've made an error in my minimization.

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(originally uploaded to jsfiddle)

Hope you can help, hope this is the correct place to post!

Nick Alexeev
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Kyle93
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    What is the \$\Phi\$-symbol? Same for `x` – jippie Mar 06 '13 at 18:39
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    @jippie X is typically a don't care state but i've never seen the Phi symbol before. – Dean Mar 06 '13 at 19:31
  • @Dean that's why I started to doubt X too. – jippie Mar 06 '13 at 19:32
  • They are different forms of "Don't care" the zero with 1 on it is "don't care" from the excitation table where as "x" is simply don't care in the map itself. Meaning they can be either 0 or 1. It does not matter, you can use them to make minimization easier. I'm unsure if it's just a computing concept, as I do Computer Science not electronics. However, I hope that helps you understand and you can help! – Kyle93 Mar 06 '13 at 19:32
  • @Dean As I said for Jippie, its another form of don't care. For all purposes treat them the same – Kyle93 Mar 06 '13 at 19:33
  • Your first table has 1 0 X X, which you have grouped together. It has a zero and can't be grouped. So for the first table I make it JA = ¬B¬C¬D. Is this intentional or is this your problem? – Dean Mar 06 '13 at 19:40
  • @Dean Thanks! That was my issue, can't believe I over looked that! Thanks, feel free to answer the question with that reply in an answer format and I'll pick as best answer. Thanks again :) – Kyle93 Mar 06 '13 at 19:47

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Assuming that \$\Phi\$ is the same as X (don't care), I would make the following corrections:

JA = ¬B ¬C ¬D
Here you covered a 0 that you shouldn't, so you have to make a smaller minterm.

KA = D
Here you can make a bigger minterm because the 2*2 are above the minterm only contains don't cares.

KC = ¬D
Again, you can meg a bigger minterm. You don't have to add C because the first column only contains don't cares and ¬D covers the first and the last column.

totymedli
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  • Thanks, I just implemented the minimized solutions you posted they work perfectly. For them do I need to change my groupings at all or are they fine? I said I would give best answer to Dean as he was the first one to post a working solution. However when I can upvote I will upvote you as you posted the answer plus some helpful minimization and explanations! Thanks – Kyle93 Mar 06 '13 at 19:54
  • @Kyle93 I think that the other solutions are minimal realizations so they will be fine. Also I answered your question (find the solution) before Dean, it just took me a while to review all the solutions and write a proper answer, thats why my answer has a 7 min delay. But nevermind, do what you think is good. – totymedli Mar 06 '13 at 20:08
  • well unless dean replies your answer has it. So I will give him a bit to reply then select you. I'm only basing the time on what I can see. It says you answered 24 mins ago while he commented 30 mins ago, thus me believing he had the solution. Regardless, thank you very much for your help! – Kyle93 Mar 06 '13 at 20:11