Simulation and Verification

[raspecht]

First of all, I have gone through pretty significant steps in trying to debug what is going on.  However, my main issue is that if my test bench becomes to complicated...either I get an unexpected error or a gui not responding error.   Worse yet, is that the logic internally will beging to act ranodmly (e.g. a singal will randomly change state).   In a test bench, when a process kicks off, it prevents another process from continuing to run (it halts it for a pseudo random period of time).

I have submitted a webcase, but i'm trying to see what is going on here has happened to other people.  I have had this issue with 12.3, 13.3, and now 13.4 on two different machines.  Both are running Win7 Enterprise 64-bit.  The largest difference between the two machines was the video card (AMD vs nVidia). 

A good thing is that if I run a simple test bench, it appears to be okay.  However, I'm in a spartan 6.  This is not a small or trivial device and thus for long term verificaiton, a small or trivial test bench will not suffice.  I really want to keep a single workflow and not have to have a seperate simulator (like Aldec) and pay addtionally for it.   I've been okay not being able to display variables and some of the other limits, but getting different results (like 'stable not working at all 'quiet is working) on the same signal is driving me up a wall.   Doing verificaiton by bench testing on 40k lines of VHDL will be the death of me if I can't simulate properly.

[jays_xil_giga]

   I have also had ISIM crash when using windows 7 with a large simulation test bench.  I can run about 8us of simulation before windows 7 crashes with a GUI not responding.  I have put up with this ever since going to windows 7 with several versions of ISE.  At this point I have setup a dual boot machine with 32bit XP and windows 7. Anytime I wish to run ISIM I reboot to 32bit XP. The exact same test bench will run without crashes in 32bit XP. I will note that 64bit XP will also crash ISIM.

   For several releases Xilinx said they would get an analog trace format into ISIM like Modelsim had. They never have and in fact took the note away in the user guide for ISIM that said they would do so in a future release.  Many users have asked for this function which Xilinx has never gotten into ISIM.     

   Because of these I expect that Xilinx will never fix the problems in ISIM like it crashing in windows 7. I will add the just last week I was doing some code editing in ISE 13.4 with windows 7and all of a sudden the ISE editor stopped responding just like does for ISIM. 

[debrajr]

These crashes are mostly localised to Windows 7 64 bit machines. We have already received similar issues and these are already been worked upon. The future releases of the tool (post 13.4) would have more stable operation when it comes to running simulation in Win 7 64 bit platform.

1. If you have any Win XP 32/64 bit or Win 7 32 bit or LINUX machine, try using them in case you are getting a crash with Win 7 64 bit machine as a workaround.
2. If you are getting any Error/Warning/Fatal Error before the tool is crashing, it would be helpful if you can raise a webcase with Xilinx highlighting that message and it would be handled accordingly.

[jays_xil_giga · Accepted solution]

The issues I had with my ISIM simulation crashing in windows 7 appears to be fixed in the 13.4 release. I was able to run the simulation for quite a period of time in 13.4 after the period that I would get a windows crash in 13.3 or earlier ISE versions.

[alanbrennan]

Glad you're up and running Jay. Afraid to report that I'm having the same issues as you they won't go away with the update to 13.4. Like yourself, I'm simulating a Spartan 6 device. My simulation is cut right down to contain only the block of code I'm currently working on, but it's still giving the isimgui.exe has stopped working error from windows. The Xilinx error is "A Xilinx Application has encountered an unexpected error. It is recommended that you save any unsaved work in the event that this condition persist. For further assistance, please consult the Answers Database and other online resources at http://support.xilinx.com."

So afraid it's still broken. I'm on the illfated 64-bit windows 7 machine. Any help please Xilinx? I can't design this without a simulator. Incidentally, why did Xilinx move away from Modelsim towards ISim? I wouldn't mind but there are so many features that are missing. No signal spy. No variables... Broken attribute handling... It's a real shame. It's forcing users to spend money twice.

[primoz_beltram]

Sometimes it helps to look at Windows Event Log (Control Panel -> Administartive Tools -> Event Viewer) messages and check for (error) events at time you hit the application crash.

Hopefully you can see some pattern of events that you can connect with application chrash.

[alanbrennan]

Interesting idea. Here's the event log for the failure:

Faulting application name: isimgui.exe, version: 0.0.0.0, time stamp: 0x4f082a27

Faulting module name: libSimBridgeData.dll, version: 0.0.0.0, time stamp: 0x4f07b60e

Exception code: 0xc0000005

Fault offset: 0x000000000000a5cf

Faulting process id: 0x1988

Faulting application start time: 0x01cd114e723b6863

Faulting application path: C:\Xilinx\13.4\ISE_DS\ISE\bin\nt64\unwrapped\isimgui.exe

Faulting module path: C:\Xilinx\13.4\ISE_DS\ISE\lib\nt64\libSimBridgeData.dll

Report Id: 90ac342d-7d43-11e1-9a4f-782bcbae99a0

Xilinx? Does this mean anything to you. ISim is still broken... I haven't moved back to Modelsim yet, but seriously, it's looking more and more like a good idea...

[rcingham]

Perhaps a silly question, but does it crash the same way every time?
The 'Faulting process id' and 'Faulting application start time' will change, of course...

[ondrisko]

By the same if I am simulating simple design no problem, but with growing number of loged signals and also complexity of design the time is shorter before crash. One of designs I have with lot of signals si crashing after 1-2us of simulation. The only way to simulate is to remove most of signals and look only on few. However it is hard to find bug in comlicated design.

[xilinxer_the_second]

I know, it's a bit unconstructive, but:

It's a pitty that ISim is still so unstable eventhough it is none of the first versions (v13...) . Sometimes it's a real challange just to simulate parts of a virtex 6 project.