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dwbarker
Visitor
Visitor
331 Views
Registered: ‎07-23-2021

Simulator waveform does not display

Hi,

 

Vivado will no longer display waveforms after performing a simulation.  I have stripped everything away so that all that is left is an extremely simplistic simulation.  I've attached the testbench that I am running ('test_tb.vhd').  As you can see there is nothing complicated about it.  I've also attached a screenshot that shows the simulator after it runs ('screenshot.png').  You can see that there are no waveforms that display.  I've also attached the output on the TCL console.  I've run this simulation on another Linux machine and it works fine.  I've also uninstalled Vivado and completely wiped every trace of it from my machine and reinstalled and I get the same result.

Can anyone please tell me what is going on?  Everything used to work on this machine and now it has magically stopped working.

 

Thanks

Doug

screenshot.png
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4 Replies
joancab
Teacher
Teacher
317 Views
Registered: ‎05-11-2015

You've got a clue here:

joancab_0-1627050086642.png

Typically a test bench instantiates another module, the DUT or Device Under Test and the DUT's inputs and outputs are shown automatically.

In your case, you have a testbench that tests nothing. I really don't know what to suggest as I don't know what you want to achieve.

Maybe adding a dummy process to it?

 

 

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dwbarker
Visitor
Visitor
316 Views
Registered: ‎07-23-2021

Understand - I originally had a much more sophisticated testbench and  a module under test and when that didn't produce waveforms I started stripping everything back to the simplest possible configuration to remove other variables from the mix.  Although the testbench does not instantiate any DUT, it should still run and show some waveforms for the two signals in there - and it does indeed work as expected on my other Linux machine.

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joancab
Teacher
Teacher
293 Views
Registered: ‎05-11-2015

I do the same, based on the principle "no code no bugs", but there is a limit to that:

image.jpg
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dwbarker
Visitor
Visitor
171 Views
Registered: ‎07-23-2021

Turns out the problem was Ubuntu.  We had to do an OS recovery to fix the problem.  Weird how it affected Vivado as it did.

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