I want to create a circuit according to table below. CLK, MOD and RST are inputs, Q1 Q2 Q3 - outputs. The signal on the output should change at the active edge of CLK. What is the best approach to construct such a sequential logic? I only know how to deal with combinational logic so far. Any hint of where to start?

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closed as off-topic by Bimpelrekkie, uint128_t, Wesley Lee, ThreePhaseEel, nidhin Feb 23 '17 at 12:08

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    \$\begingroup\$ I'm voting to close this question as off-topic because in this homework assignment you have not show what you have tried. No doubt there are examples in your textbook and/or shown in the classes you took. \$\endgroup\$ – Bimpelrekkie Feb 19 '17 at 12:55
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    \$\begingroup\$ Hint: Karnaugh diagram. Instead of CLK, you have three counter inputs to the logic table. You may want to reduce the RST variable first. \$\endgroup\$ – Janka Feb 19 '17 at 13:12
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    \$\begingroup\$ First of all @FakeMoustache, how do you know its homework? All I see is that he has some task associated with school. Secondly, why does someone have to type up pages of work that lead nowhere? How does that make sense? What measure of work is necessary to prove to you that someone doesnt even know where to begin? Who is obligated on a Q&A site to produce the answer, as best they can, as they ask the question? If youre uncomfortable answering the specific prb (perhaps you dont know how), instead of criticizing the questioner why dont you give a broader conceptual explanation of how instead. \$\endgroup\$ – CogitoErgoCogitoSum Feb 19 '17 at 18:11
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    \$\begingroup\$ I vote to keep this question open because despite @FakeMoustache inability or unwillingness to answer, I think its a legitimate and valuable question worthy of a response, and contributes nicely to the discussion topics that this site is based on. The point of this site is to answer questions that other people, who are skilled to the point of triviality, can competently and reliably answer. Who are you to shut down a question you arrogantly perceive to be "beneath you"? Sorry if youre not entertained enough, but that isnt the purpose of this site. \$\endgroup\$ – CogitoErgoCogitoSum Feb 19 '17 at 18:15
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    \$\begingroup\$ @FakeMoustache You were asked an explicit question directed at you specifically for your amazing skills. On Feb 19th, 2017. Why havent you responded yet? If youre going to quote me with italics, the least you could do is get past the first sentence before you criticize it, fool. Your arrogant retort was completely unnecessary and unfounded had you bothered to read just a sentence more than you did. \$\endgroup\$ – CogitoErgoCogitoSum May 27 '17 at 17:56

I guess you want to implement a moore machine. Here is some guidance on how to implement such. Below the structure of moore machines.

Structure of a moore machine

Some other thoughts:

  • The next state logic will probably be a counter that counts 0 to 6.
  • RST will reset the counter.
  • The output logic will then - depending on the counter output and the MOD input - set the output Q according your table.
  • Buffer MOD so we don't get a mealy.

I hope this could help you at least a little bit.


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