Prerequisites for Dynamic Abstract Generation

Dynamic Abstract Generation uses the Wire constraint group that is specified in the Wire Editing section of the Layout Editor options form.

The prerequisites for Dynamic Abstract Generation are as follows:

• Valid vias and valid layers must be defined in the specified constraint group. If valid vias and valid layers are not present in the constraint group, a warning message is displayed in the CIW stating that the required information be added in the technology file.
• The minSpacing and minWidth layer rules must be present in the technology file. During Dynamic Abstract Generation, the constraint groups are searched for layer rules in the following order:
  • Wire (user-defined) constraint group
  • LefDefaultRouteSpec constraint group by type
  • LefDefaultRouteSpec constraint group by name
  • Foundry constraint group
  
  For example, if the minSpacing value for metal3 is required, the minSpacing value is first searched for in the Wire constraint group. If the minSpacing value is found in the Wire constraint group, it is used. If the minSpacing value is not found in the Wire constraint group, the minSpacing value is searched for in the LefDefaultRouteSpec constraint group first by type and then by name. If the minSpacing value is not found in the LefDefaultRouteSpec constraint group too, the Foundry constraint group is searched for the minSpacing value.
• Net and pin technology purpose must be present in the technology file. During Dynamic Abstract Generation, the net and pin purpose is used for net extraction and pin creation. If the net and pin purpose is not present in the technology file, Dynamic Abstract Generation adds the layer purpose pair information in the technology file, provided the write permission is available for the technology file.
• If an alternate foundry constraint group (AFCG) is defined in the .cdsenv file, Dynamic Abstract Generator replaces the foundry constraint group and uses the specified AFCG instead.
  You can specify an AFCG by setting the following environment variable in your .cdsenv file:

 cdba.layout AlternateFoundryCG string "AFCG_name"

Related Topics

Wire Constraint Group

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