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dnovick
Observer
Observer
8,203 Views
Registered: ‎06-16-2016

Forcing values in ISim is not working

Greetings.

 

I'm using ISim 14.7 as part of the latest WebPACK distribution. I am trying to force constant values from my simulation. I've tried to set both wires and regs to 1 using both the GUI and the ISim command prompt. Although the command appears to be accepted, the forced values never appear. I want to believe that this is user error, but for the life of me, I cannot see where I'm doing anything wrong. I've searched online, looked at the docs, etc...all to no avail.

 

Help?

 

Thanks,

Dave

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5 Replies
syedz
Moderator
Moderator
8,179 Views
Registered: ‎01-16-2013

@dnovick,

 

Check if the following forums threads helps:

https://forums.xilinx.com/t5/Simulation-and-Verification/Changing-register-value-during-simulation/td-p/42526

 

https://forums.xilinx.com/t5/Simulation-and-Verification/problem-while-giving-input-values-in-simulation-window-please/td-p/300985

 

--Syed

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dnovick
Observer
Observer
8,170 Views
Registered: ‎06-16-2016

Thanks for the response. Unfortunately, this doesn't address my issue...for a couple of reasons:

 

- I'm not only trying to force values via the command line, but via the GUI, and it doesn't appear to work "as advertised." The GUI is setup to use the "force" ISim command (I see this in the console window), and so I expect it to work.

 

- According to what I read regarding "put", it is overridden by any HDL assignment. This is different than "force" whose values are supposed to override those written in the HDL. 

 

Please note: my concern isn't that I can't do what I need to do by, for example, changing my testbed. My concern is that an advertised feature of the application does not seem to work as documented. I'm hoping to understand why...again, defaulting to the possibility that I'm doing something wrong.

 

Thanks.

Dave

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tsjorgensen
Explorer
Explorer
8,147 Views
Registered: ‎09-13-2011

Forcing works fine for me on Windows 7 64 with full license. Does it give you something like this in the console window?:

# isim force add {/domain_cross_tb/dut/wr_release} 1 -radix hex

 

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dnovick
Observer
Observer
8,138 Views
Registered: ‎06-16-2016

I'm on Win 8.1 64 bit using WebPACK.

 

Yes, I see the console output when I try to configure a forced value in the GUI.

 

Dave

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tsjorgensen
Explorer
Explorer
8,134 Views
Registered: ‎09-13-2011

Isim doesn't work very well on higher than Windows 7 32-bit, on my 64-bit I have trouble with vectors getting garbled and it seems to have a tendency of crashing when long vectors are found in the output. I would not recommend using ISE on Windows >= 8. If you need it to be ISE (for instance for older devices) I would recommend finding a Windows 7 32-bit machine that Microsoft yet haven't managed to upgrade to Windows 10...

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