I hope this helps . I have a few problems with a fairly simple state machine I made. No matter what I do, the signal startS1, startS2, enS and mS always stays unsigned in simulation even when I hit the reset button and I can't figure out why. There's a component in the mix, but I did test the component and it works perfectly. I hope you can help me! , Add RESET to your process sensitivity list.
fixed the issue. Will look into that further In a state machine, next state is a combinatorial logic function of both input and current state. In the case you are describing, the same cause (Initialized state) seems to be able to trigger two different effects (either InProgress or Error state). I guess that there is a hidden input whose value makes the difference. I also guess that this input is received during transition from Uninitialized to Initialized.