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August West

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Instantiating a netlist
Jun 21^st, 2005, 8:04pm

Can someone that is wise to the ways of Cadence's ADE please enlighten me on the following bit of trivia?

How does one go about instantiating a netlist in a schematic? I have a Spice netlist for a large block that I would like to include in my simulation, but I don't want to go to the considerable trouble of drawing a full schematic for it. So I would just like to add a block to my schematic and have the block point to a subcircuit described in a Spice netlist.

Is that possible? It seems like I can create text-based cellviews, but they are all associated with an HDL rather than a Spice or Spectre netlist.

Thanks so much for your help.

August

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Andrew Beckett

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Re: Instantiating a netlist
Reply #1 - Jun 21^st, 2005, 8:26pm

August,

There's no spectre text view as such in DFII (there are enhancement requests asking for this), but you can treat the textual subckt as a model rather like any other model.

So here's what you need to do:

Create a symbol with pins corresponding to the subckt in your text file
Edit the CDF (Tools->CDF->Edit, and change to Base CDF Type, and select the cellname of the symbol you just created
Scroll down to the simulation information section of the CDF, and hit Edit. Select spectre as the simulator.
Set component name to the subckt name, inst parameters to the names of any parameters to be passed in (you'll need to define these in the parameters section of the CDF too), and termOrder to the names of the pins in the same order that they appear in the subckt.
If you need the ability to set the subckt name on the instance, add a CDF parameter called "model", and add "model" in the otherParameters list for the spectre simInfo.
In ADE, specify the path to your subckt file in the Setup->Model Libraries form (you can always use a relative path and add the directory to the include path specified in Setup->Simulation Files)

Hope that's clear enough.

Regards,

Andrew.

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August West

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Re: Instantiating a netlist
Reply #2 - Jun 21^st, 2005, 9:57pm

Andrew,
Thank you so much for your help. I have followed your instructions but still cannot get it working. After doing the things you suggest I try to run the simulator and ADE complains that ...

ERROR: Netlister: unable to descent into any of the views defined in the view list: "spectre cmos_sch schematic veriloga ahdl" for instance Mixer in cell TLS.
Either add one of these views to: Library: receiver Cell: mixer or modify the view list to contain an existing view.

I guess I was expecting the spectre view to be created when I followed your procedure, but it was not.

I was considering creating it from the "Create cellview from cellview" command, but was not sure what type to make it. So I am still lost. Do you have any further hints to give me?

August

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August West

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Re: Instantiating a netlist
Reply #3 - Jun 22^nd, 2005, 5:58pm

I got it working, and I'll describe how I did it, but cannot imagine that this is the recommended approach.

First, I followed Andrew's instructions. Then, I went into the file system where the symbol I was using to represent the subcircuit was stored, and I copied its directory and its contents and renamed it 'spectre'. In particular I did the following ...
Code:

cd .../mixer
cp -r symbol spectre

Once I did that, the spectre view appeared as one of the views and everything worked properly.

August

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Paul

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Re: Instantiating a netlist
Reply #4 - Jun 23^rd, 2005, 1:26am

August,

indeed the netlister is looking for a view in the view list when descending the hierarchy. For this reason, you either have to add the symbol view to the view list, which you have to be careful with because all components have symbol views, or you have to copy you symbol to another view name, which is what you did.

You can also have a look at the following post:
http://www.designers-guide.org/Forum/?board=circuit;action=display;num=111894018...

Paul

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Andrew Beckett Senior Fellow Offline Life, don't talk to me about Life... Posts: 1742 Bracknell, UK	Re: Instantiating a netlist Reply #5 - Jun 23^rd, 2005, 4:03am Er, whoops, I forgot to mention creating the "stopping" view. Normally you wouldn't do this at the UNIX level, but copy the symbol view to a spectre view in the library manager, or open the symbol and do a Design->Save As to save it to a spectre view. Regards, Andrew.
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August West Community Member Offline I'll get up and fly away Posts: 71	Re: Instantiating a netlist Reply #6 - Jun 23^rd, 2005, 9:51am Thanks guys. I knew there had to be a better way. August
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jbdavid Community Fellow Offline Posts: 378 Silicon Valley	Re: Instantiating a netlist Reply #7 - Aug 3^rd, 2006, 4:29am There is actually a TOOL that can create the simulation stopping views from a pin list.. Last time I used it was in 4.4.5 though.. useful if you want to build a design kit with a script. Jonathan
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sheldon

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Re: Instantiating a netlist
Reply #8 - Aug 4^th, 2006, 10:32pm

Greetings,

There is one other approach you might want to look into,
however, you will need to use the Hierarchy Editor.

1) Create a configuration

2) For the instance that you want to netlist as a text file select
Set Cell View / Set Instance View / Set Occurrence View --> Source File

3) Enter the Source File location in the Enter the Sourcefile Location window.
There is a browser so you won't need the whole path.

Note:
You will still need to properly prepare the netlist for simulation, for example,
creating a symbol for the schematic.

Best Regards,

Sheldon

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