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I try to build a stepper based on a book. I have been looking for the error for hours now, but still could not find it. Maybe you can help me with this issue?

This is my stepper: This is my stepper

This is a working example: This is a working example

The squares are 1 bit memories. Somehow when I connect the last output with the left input, the wire gets red, which indicates an error somewhere. If those are not connected, the stepper works just fine: Somehow this works

Many thanks in advance :)

Edit: I copy the internal structure of those squares:

Mine looks like the following:

enter image description here

In the working example it is like that:

enter image description here

MetaLogicianWannabe
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  • Are those latches or flip-flops? – a concerned citizen May 15 '21 at 22:44
  • I put all the info in the original post. I guess those are latches, kind of? – MetaLogicianWannabe May 15 '21 at 23:01
  • Building the first circuit using the boxes labeled CPU MEM 1 works. This is odd... I have two logically equivalent structures, and one time it works, other times it does not work. Is this a bug in Logisim, or a misconfiguration/error from my part? – MetaLogicianWannabe May 16 '21 at 06:27
  • That's a latch, not a flip-flop. See[this](https://electronics.stackexchange.com/q/532999/95619). You could try adding some sort of delay for the two final gates. – a concerned citizen May 16 '21 at 07:06
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    Logisim shows an error on several conditions, for example if one line is driven by multiple outputs of different level, or if you draw a feedback circuit before connecting other inputs. If you have a feedback circuit (and you have) where the error is fed back, you need to reset the simulation. See the menu "Simulation". – the busybee May 16 '21 at 13:21

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