Finite State Machine Question

WBahn

Joined Mar 31, 2012
24,981
You have given us virtually nothing to go on. Just knowing that something didn't work gives no clue as to why it might not have worked. You need to provide details, preferably a screen shot of the schematic YOU used, information about this unidentified app you used to simulate it, and the waveforms for the relevant signals from the simulation. For all we can tell, the problem may be nothing more than you are not properly initializing your DFF states. Or it might be that you are not providing an unambiguous signal level to some asynchronous input. We aren't mind readers.
 

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walrusa

Joined May 10, 2016
2
Uploaded a screenshot. I am using Logic Simulator Pro (not sure how accurate this simulation is). The app doesn't include waveforms for the signals, but I rewired it multiple times in the App, so I don't think I made a mistake of wiring stuff wrong. Thanks for the response.
 

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WBahn

Joined Mar 31, 2012
24,981
Uploaded a screenshot. I am using Logic Simulator Pro (not sure how accurate this simulation is). The app doesn't include waveforms for the signals, but I rewired it multiple times in the App, so I don't think I made a mistake of wiring stuff wrong. Thanks for the response.
So.... what indicates HI and LO? Why make us (the people you are asking for free help) have to figure these kinds of things out?

My best guess is that a blue wire is HI and a white wire is LO?

If so, does it make sense that both the Q and Q' outputs of both flip flops are HI?

What does CLR' and PRE' default to if left unconnected?

It appears that you have possible shorts in three places (the outputs of the top DFF and the inputs of the two bottom AND gates). The colors of the wires imply that they aren't actually shorted, but it's then hard to tell which wire is actually connected to which pin.
 
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