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Simulating Verilog-A modules, including VPI, with Spectre

fgarcia


Hello,

I am trying to instantiate a Verilog-A component which includes a VPI call to a C++ library, but I each time I run Spectre simulator I get the following error:

                  Error found by spectre during AHDL read-in.
                      ERROR (VACOMP-2259): "$hello<<--? ;"


The Verilog-A module (including VPI call) is functional and has been verified using NCVerilog and NCSim.
When trying to simulate in Spectre, this module is included with the following sentence:

                   ahdl_include "altered_non_linear_drift.va"

Which is the proper way to include this kind of elements in a standard Spectre netlist?

Thank you in advance

  • I am trying to do the same thing (and got the same error). Did you manage to find a solution? Thanks
  • There is no support for VPI in spectre so you cannot add custom system tasks such as this. Are you really both trying to call a custom system task in Verilog-A? I've not seen anyone attempting to do this before so it seems a little odd that there are two of you within a few days... Regards, Andrew
  • Dear Andrew, the purpose of this action is to develop custom C++ functions to be used in our models.
    I was looking for the Spectre (or the internal AHDL compiler) options equivalent to -sv_lib ./libvpi.so -loadvpi ./libvpi.so:registerHelloSystfs in NC.
    Maybe there exists another way to perform such actions in Spectre: Do you know a way to call user defined C++ functions from, for example, a user defined subcircuit? That would be perfect.

    Thanks in advance
  • Dear Dime, Till know I am unable to simulate this code.

  • There is documented support in spectre for "Netlist Compiled Functions" - these are functions you can implement in C/C++ and allow to be called from a spectre netlist. I'm not sure these will quite do what you want - they are for complex calculations of netlist or model parameters - but are not for behavioural modelling (so they can't be called with non-constant expressions, such as node voltages or device currents). You can find out about them using `cds_root spectre`/tools/bin/cdnshelp and searching for "Netlist Compiled Functions".

    There is also the C Model Interface (CMI) which is for developing device models. The documentation for this is not provided out of the box - you need to have access to product 32501 (Virtuoso ® Spectre Model Interface Option). I suspect this would be overkill for your needs - it's really about integrating detailed device models into spectre.

    Apart from that, there's no foreign model interface in spectre.

    Regards,

    Andrew.

  • That's exactly what I have been looking for. I would search about it. Thanks!

  • Dear Andrew, 

    Thanks for the reply. In my case, I might need to work with the C Model Interface as I am working on device modeling. Could you please provide me with more details on how to access the CMI documentation? 

    Best,

    Marco

  • Marco,

    You need to have the license I mentioned earlier, and then run "cmiExtract" to extract the documentation.
    I would suggest contact customer support for more details - you should consider very carefully (and with some advice from us) as to whether CMI is the right way forward on this.

    Regards,

    Andrew.

  • Dear Andrew, I have followed your advice and studied the possible solutions. cmiExtract also provides a series of xml interfaces to be used when developing compat models using adms. However, these files are related to adms v2.7. Are the updated ones available? Thanks in advance, Fernando
  • Hi Andrew. Can C-Model work together with Monte-Carlo variation parameters in “statistics” section of the model file ?

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