Virtual Connectivity

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Normally, if the layout connectivity extractor finds disjoint, unconnected geometries with the same net name text attached, the extractor will view this as an open circuit.

  • Virtual connection results in the extraction of a single net from two or more disjoint physical nets when the physical net segments share the same name.
  • Virtual connectivity is triggered by the rule file VIRTUAL CONNECT COLON and VIRTUAL CONNECT NAME specification statements.
  • Virtual connectivity can also be specified through the Calibre Interactive GUI.

VIRTUAL CONNECT COLON

Virtual Connect Colon is used to virtually connect nets that share a common prefix before a colon, like VDD:1, VDD:2, and so forth.

If you specify YES, then the connectivity extractor first strips off all characters from the first colon to the end of the label names.

Next, the extractor forms a virtual connection between any two labels that have the same name and that originally contained a colon.

Colons can appear anywhere in the name with the exception that a colon at the beginning of a name is treated as a regular character (that is, it has no special effect).

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up to the first colon character encountered

The colon is discarded in the extracted net name

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VIRTUAL CONNECT NAME

Virtual Connect Name virtually connects nets that share the same name

Each name is a net name and can be optionally enclosed in quotes.

The connectivity extractor forms a virtual connection between any two labels having the same name such that the label name appears in a Virtual Connect Name specification statement in the rule file.

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VIRTUAL CONNECT NAME ? == Connect all nets by name

Note that if Virtual Connect Colon YES is also specified, then Virtual Connect Name operates on names after all colon suffixes have been stripped off.

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reference

Calibre Fundamentals: Performing DRC/LVS Student Workbook

Calibre Verification User’s Manual Software Version 2019.3 Document Revision 7