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Nov 28th, 2020, 3:47am
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pss sweep with veriloga (Read 938 times)
eeBismarck
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pss sweep with veriloga
Nov 20th, 2017, 5:00am
 
Q1
I am simulating an oscillator 24MHz with trimming (8-bit) ability. There is a variable called "TRIM_CODE" as decimal value in my test bench. I use a veriloga model to translate TRIM_CODE into binary code and connect them to my oscillator. Then I use pss to check frequency and some times it can't convergence.
Q2
TO solve convergence problem, I remove veriloga model, and make 8 vdc by setting 8 variable D7...D0 in global variable from TRIM_CODE by equations. It seems convergence problem solved, however, if I sweep TRIM_CODE in pss, the result doesn't change. Only default value of TRIM_CODE is calculated by pss.

Conclusion
I just want to know how I can sweep TRIM_CODE in pss without such strange problem ? Is there any one can help ?

Thanks !
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Geoffrey_Coram
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Re: pss sweep with veriloga
Reply #1 - Nov 20th, 2017, 7:48am
 
You should probably post the code for your veriloga model; I can think of a couple ways you might be converting a design variable to binary.
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sheldon
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Re: pss sweep with veriloga
Reply #2 - Dec 1st, 2017, 5:30pm
 
eeBismark,

  Not sure I understand what you are saying in Q2. It seems like you
are saying that you are tuning the oscillator during a PSS simulation.
In that case, there would be multiple steady-state solutions, one for
each sweep value. Not sure that this use model will work.

                                                                      Sheldon
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