Output to FastCap and FastHenry

edited July 2010 in General
A nice feature enhancement would be the ability to export layers to FastCap and FastHenry.

I think that this can be done with the Ruby scripts so maybe I will take a whack at it. If anyone else has already done this it would be great if you can share.

Oliver

Comments

  • edited July 2010

    Hi Oliver,

    is there any specification about the format required by these programs?
    I am not familiar with those myself.

    Best regards,

    Matthias

  • edited July 2010
    Matthias,

    They are both open formats. See this link:

    http://www.fastfieldsolvers.com/links.htm

    FastCap has a particularly simple file format, but it would benefit from pre-tessellation.

    This would allow folks to model their GDSII files better.

    Oliver
  • edited 11:46PM

    Hi Oliver,

    I had a brief look into the documentation but I am not quite sure about the tesselation issue. There seems to be a tool that generates a mesh for a rectangular geometry and create .qui files that you can include, but I understand that it's more common to generate the mesh directly.

    Is there any more material I could look at? In particular I assume there are some guidelines how to choose the mesh density or the tesselation strategy for example.

    I have to admit that the topic is new to me.

    Best regards,

    Matthias

  • edited 11:46PM
    Matthias,

    A parameter to control the mesh density would be nice.

    I would think that breaking things into rectangles would work well for GDSII files.

    Oliver
  • edited 11:46PM

    Hi Oliver,

    I am trying to make myself familiar with FastCap and FastHenry. I wonder what to do with non-rectangular features - I assume that decomposing them into rectangles and triangles would be a good starting point.

    Best regards,

    Matthias

  • edited 11:46PM
    I'm aware this comment is from a while ago ... I'm currently working on finding a program to breakdown these non-rectangular features into the FastCap .qui format. Did you find a way to do this or is this an unsolved problem?

    Mike
  • edited 11:46PM

    Hi Mike,

    no sorry - I did not pursue this thread much further. Decomposition into parts is available but I don't know the requirements of FastCap. I understood this is tessellation and not just decomposition. I assume that a dumb trapezoid decomposition is not really helpful.

    Any inputs?

    Matthias

  • Hi all,

    I don't know if this might help, but FastCap is integrated into another open source ASIC toolset: https://github.com/wrcad/xictools. Possibly, it may be an inspiration how to implement FastCap&FastHenry into Klayout.

    Regards,
    Michael

  • A better link is : https://github.com/yuchsiao/caplet :
    -. caplet_gds2geo is python script to change the .GDS file into a .geo file (ascii 3D file)
    -. caplet_geo has to be compiled (C++) and is changing .geo file into .qui that can be read by FastCap

    I succeeded to compile all the files, get the .geo file, ... but failed to get the .qui file :neutral:

    Laurent

  • Hi Laurent,

    thanks for the link. Just to confirm, the caplet_geo generates .qui files, you must specify "--type pwc" for "caplet_geo_cli" program or you can execute FastCap directly from gui. I tried it with FastCap from xictools.

    Michael

  • Hi Michael,

    Did you succeeded to make a proper C extraction from a GDS ? or someone else ?
    If yes, can you share some example files (GDS, qui and spice file) ?
    It seems that xictools is the software to use ...

    Laurent

  • Dear all,

    thanks for the pointers.

    FastCap and FastHenry integration / interfacing is on my to do list. However, as of now, I have not taken a deeper look into that topic yet. I feel that in order to be useful, some integration on a lower level is required - specifically within the netlist extraction framework.

    Matthias

  • Hi Michael,

    Did you succeeded to make a proper C extraction from a GDS ? or someone else ?
    If yes, can you share some example files (GDS, qui and spice file) ?
    It seems that xictools is the software to use ...

    Laurent

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