Black simulation screen in xilinx 9.1

[p11]

Please someone suggest me that what error mainly causes this type of simulation output in ISE 9.1 VHDL./Usually the simulation screen is green black combination , nut just due to assignment of a signal in the sensitivity list of a process , it turned totally black as shown above although the output showing is error free

 

[BradtheRad]

I guess you're talking about scope traces? Can you verify the scale factor of your scope traces?

Don't know about your software, but when scope traces go flat in Falstad's interactive simulator, it's because all values went to infinity for some reason as I was working. The simulator automatically scales the values to fit the finite space. This creates a teeny tiny scaling coefficient. It does not get corrected when normal values resume. Scope waveforms no longer appear.

 

[dpaul]

Please someone suggest me that what error mainly causes this type of simulation output in ISE 9.1 VHDL.

First and foremost, please get out of the ancient ISE 9.1. Use Vivado.

You have just posted the screenshot and nothing else. I can't even read the signal names on the LHS of the screenshot properly. No VHDL code to show what is the intended behavior, no test-bench to indicate that you are driving the signals of your DUT.

Wait a minute! Have you written a test-bench in the 1st place?

Usually the simulation screen is green black combination

If there is nothing to drive your signals then you'll see no o/p. So you don't see any signal transitions.

With so little info I can only speculate.

 

[ads-ee]

First and foremost, please get out of the ancient ISE 9.1. Use Vivado.

Or you could suggest ISE 14.7 as they might be using something older than the 7 series and above.

If there is nothing to drive your signals then you'll see no o/p. So you don't see any signal transitions.

well you would likely see red instead. I'm more inclined to believe there is an infinite loop somewhere and the simulation hasn't gone past 0 ns and the simulators iteration limit was exceeded and the simulator stops.

With so little info I can only speculate.

Well this is PAR for the course with p11.

And just to be clear I'm not trying to answer p11's question, I'm just responding to dpaul's reply. ;-)