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Parasitic devices/probes in the schematic --> How to fix the layout connectivity (flightlines) in VXL?

Wim Verhaegen

Hi all,

We are using multiple parasitic elements or simulation probes in our schematics. We are using the "lvsIgnore" and the "lxRemoveDevice" statements to filter them out when creating the cdl netlist. What happens is the netlist will ignore these devices en shorts both of their terminals.

When we generate the layout from source in VXL, we would like it to do the same...The devices aren't generated but the terminals are still seen as two different nets...

What can we do?

Best regards

Wim Verhaegen

Parents

  • Hi Wim,

    In IC61, the lxRemoveDevice information should be placed in a LAM file (Library and Attributes Mapping file). This file needs to go in

    <libName>.cadence/dfII/cph/lam/cph.lam

    and have contents like below (strictly speaking there are other locations it can be placed - see the documentation - search for "LAM"). Make sure you change the LIB NAME line below to match your library name:


    <!DOCTYPE LAM_FILE>
    <LIBRARY_DATA>
      <VERSION NUMBER="0.3" />
      <LOGICAL>
        <LIB NAME="mylib" >
          <CELL NAME="presistor" >
            <VIEW NAME="symbol" >
              <REMOVE_DEVICE>(short(PLUS MINUS))</REMOVE_DEVICE>
            </VIEW>
          </CELL>
          <CELL NAME="pinductor" >
            <VIEW NAME="symbol" >
              <REMOVE_DEVICE>(short(PLUS MINUS))</REMOVE_DEVICE>
            </VIEW>
          </CELL>
        </LIB>
      </LOGICAL>
      <PHYSICAL/>
    </LIBRARY_DATA>


    You'll see if you start Layout XL (and Gen from Source or Update Components and Nets) and then launch Configure Physical Hierarchy, that this has seeded the information that these devices should be removed.

    Regards,

    Andrew. 

Reply

  • Hi Wim,

    In IC61, the lxRemoveDevice information should be placed in a LAM file (Library and Attributes Mapping file). This file needs to go in

    <libName>.cadence/dfII/cph/lam/cph.lam

    and have contents like below (strictly speaking there are other locations it can be placed - see the documentation - search for "LAM"). Make sure you change the LIB NAME line below to match your library name:


    <!DOCTYPE LAM_FILE>
    <LIBRARY_DATA>
      <VERSION NUMBER="0.3" />
      <LOGICAL>
        <LIB NAME="mylib" >
          <CELL NAME="presistor" >
            <VIEW NAME="symbol" >
              <REMOVE_DEVICE>(short(PLUS MINUS))</REMOVE_DEVICE>
            </VIEW>
          </CELL>
          <CELL NAME="pinductor" >
            <VIEW NAME="symbol" >
              <REMOVE_DEVICE>(short(PLUS MINUS))</REMOVE_DEVICE>
            </VIEW>
          </CELL>
        </LIB>
      </LOGICAL>
      <PHYSICAL/>
    </LIBRARY_DATA>


    You'll see if you start Layout XL (and Gen from Source or Update Components and Nets) and then launch Configure Physical Hierarchy, that this has seeded the information that these devices should be removed.

    Regards,

    Andrew. 

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