Cadence ams Stimulus file

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simopoulos

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Hello,

I am trying to simulate three inverters connected in sequence using cadence ams simulator
and a stimulus file that drives the input with a vpulse.

I cannot make it work. The input is not driven and stays at 0.3V with vdd at 1v. (All views are schematic)

I use the same stimulus file with simulator spectre and the simulation is OK!

How can I use the stimulus file with ams?
What could I make wrong?

Thanks for your help,
Thodoros.
 

Check how the ams simulation command file and netlist are connected (or integrated), post them/it, if need be.
 
How can I post the connection of them.
Can you please tell me what files or text is needed?

What I am thinking is that I use connect Rules given by cadence samples (under the insisive package).
However I use umc65nm technology. Is it possible that the rules do not match the technology?

Thanks for your help
 

simopoulos said:
How can I post the connection of them.
Click to expand...
By posting the simulation command file, and, possibly, the files which have to be included by .include statements in this former file.

simopoulos said:
Can you please tell me what files or text is needed?
Click to expand...
No, I don't know this setUp, sorry.

simopoulos said:
However I use umc65nm technology. Is it possible that the rules do not match the technology?
Click to expand...
Well possible. Check your technology file.
 
How can I post the simulation command file?

What I do to simulate is:

I open ADE and I select the config view of the design.
I set simulator to ams - define connect rules - set stimulus file (via ADE -> setup -> simulation files)
Then I "netlist and run"
---Result shows that the stimulus file is not used.

I have successfully simulated using ams but without a stimulus file. Instead I used a vpulse driving the input.
I set the views to be verilog and the simulation was OK. So I do not thing that there is actually a problem with
the connect rules. But I cannot understand how to make the tool to use the stimulus file. I don't run ams in command line.
 


Check the netlist and see if it includes your stimulus file. If not, there's something wrong with your setup. If you can't find it yourself, post the netlist, your stimulus file and a picture from your simulation files' setup.
 
The netlist does not make reference to the stimulus file stim_testams.tcl.
However I remember that when I had as simulator spectre instead of ams, the netlist file was also not referenced but the simulation was OK.

The stimulus file includes the following:

simulator lang=spectre

_vTin (tin 0) vsource type=pulse val0=0 val1=1 delay=0 rise=0.1p fall=0.1p
+ width=50p period=100p

I have attached the irun.log file, the netlist file, the simulation options that I use, the schematic and the resulting plot.

Thanks for all your help and your concern.
 

Attachments

  • irun.log.txt
    22.8 KB · Views: 89
  • netlist.txt
    3.5 KB · Views: 78
  • sim-options.png
    104 KB · Views: 143
  • test_ams.pdf
    83.1 KB · Views: 106
  • test_ams_sch.pdf
    23.2 KB · Views: 103
Last edited:

simopoulos said:
The netlist does not make reference to the stimulus file stim_testams.tcl.
However I remember that when I had as simulator spectre instead of ams, the netlist file was also not referenced but the simulation was OK.
Click to expand...
May be there's a superior file which (should) combine all of the necessary files - like with spectre.


Thank you for posting all the necessary sim. files. I'm also sure that your stimulus hasn't been included: the notice in the irun.log.txt
Code: 
Notice from spectre during topology check.
    No DC path from node `tin' to ground, Gmin installed to provide path.
... seems to underline this. Unfortunately I can't tell you, why. You could try and explicitly add your stimulus file in the AMS Options setup -> INCLUDE OPTIONS -> Options files (-f) --- see your sim-options.png .

But this is guesswork now. If this doesn't work, you probably better ask the real freaks at the Mixed-Signal Design forum of The Designer's Guide community. Should be simple now, as you already have the necessary files available.

BTW: I couldn't open the test_ams_sch.pdf, neither with Acrobat reader nor with other PDF tools. But I believe your schematic is ok, anyway! ;-)

Good luck! erikl
 
Thanks for all your help.
I will try to use a verilog tb at -f ams option.
For completeness attached is a photo of the schematic (just three inverters connected togeather and I am
trying to use a number of them with verilog view).

Regards,
Thodoros
 

Attachments

  • test_ams_sch.png
    106.6 KB · Views: 194

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