I have a few questions to ask about electronics.I am studying computer science in my first year and I have a logic design course where the professor is kind of old let's say and he expects us to study like #### for his course, and he only offers us inconceivable pdf's with things he will never explain to us so we are pretty much on our own.Now we have a project, and mine is to design and implement a Moore machine that has an input L and an output Z.The output takes (and keeps it forever, no matter the input) the value 1 whether 2 values of 0 and two values of 1 have been detected as input(i.e 0010001 will give the output 1, as well as 0111111110 or any other combination you might think).I must use D flip-flops and NAND gates only.So I have drawn this state diagram and this table(CS stands for current state and FS stands for future state, but I do not know what to do further.I know that I must draw 8 Kmaps I think but I am not sure and I have to use 3/4 flip flops.Any effort would be greatly appreciated :Denter image description here


ok so after some more research i finally managed to draw the Kmaps and i was able to extract the functions, and this is the circuit I've designed using logisim, but i don't think it is doing what i want it to do, or maybe the circuit is good but i don't understand the mechanics behind the simulator or the way the flip-flops and the clock function.Any suggestions of what may be wrong? This is the link to the .circ file that you can open with logisim


  • \$\begingroup\$ Remember that you can build OR, NOR, NOT, AND, and NAND by combining NANDs. \$\endgroup\$ – JimmyB Dec 1 '14 at 11:10
  • \$\begingroup\$ Maybe try to design a circuit which will detect and store the first 1 (or 0) bit it sees. Then combine some of those elements to the complete circuit. \$\endgroup\$ – JimmyB Dec 1 '14 at 11:12

Being kind of old myself, I expect you to study like #### too. :D

One question may help clarify the circuit you need : how does it distinguish between 2 successive states that are the same? Or alternatively : Is there a separate clock signal, not mentioned above? If so, the basic pattern of the circuit may become clear.

Ask yourself :
how many states do you have?
how many bits are required to implement all these states?

You have already given each state a unique number : it will help to write those numbers out in binary as part of each state table.

Then treat each bit of that number separately : first create a Karnaugh map for the next state for bit 0. What are the input variables for that KMap?

  • \$\begingroup\$ can you look over my circuit and give me some feedback? \$\endgroup\$ – andrei985 Dec 8 '14 at 15:46

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