lvsIgnore Property

lvsIgnore boolean { t | nil }

Description

Defines an instance as one that is generated, but ignored for check. Examples of such instances used in the Virtuoso flow are dummy instances and filler cells. Dummy instances and filler cells have an lvsIgnore property added so that the instances are ignored for check during a Check Against Source run, although the binder can still bind them correctly.

The lvsIgnore property can be set either on the schematic instance or on the layout device.

The lvsIgnore property on instances is also used by the Layout XL connectivity extractor to remove the connectivity on the instances terminals if the device is unabutted or moved away from another device that it was overlapping and drawing connectivity from. After the unabutment or the move, if the instance overlaps another device, Layout XL automatically reassigns the connectivity based on the new overlap. You can make the connectivity of a physical-only instance sticky by setting the lxStickyNet Property property on the instance.

You set the lvsIgnore property in the Add Property form.

Layout instance Add Property form
Name	`lvsIgnore`
Type	Boolean
Value	`t \| nil`

Use the Add ignore check command from the shortcut menu of an instance (or pin) to add the lvsIgnore property. For an instance (or pin) that already has the property added, the shortcut menu provides a corresponding option to remove the property.

Alternatively, you can use the Configure Physical Hierarchy Window (CPH window) to set the ignore for check properties at the cell or instance level. If any updates are made to the ignore property settings using the CPH window, Generate All From Source considers the value set using the CPH window instead of the value on the schematic. For more information, see How to Ignore Components in Physical Hierarchy.

Additional Information

By default, lvsIgnore is included in the list of propsUsedToIgnoreObjsForCheck.

Virtuoso Layout Suite XL: Connectivity Driven Editing User Guide
Product Version IC23.1, November 2023