Virtuoso XL Layout Editor User Guide

Troubleshooting Problems in the Virtuoso XL Layout Editor

Problems with Connectivity

Connections Not Made

If the software does not accept an electrical connection you make, make sure that the following information is set in the technology file:

Connectivity information in the lxRules class

lxExtractLayers (leConducting in version 4.3.4 and earlier) defines conducting layers

lxNoOverlapLayers (leOverlap in version 4.3.4 and earlier) defines layers that must not overlap

Layer information in the layerRules class

equivalentLayers (leEquivalent in version 4.3.4 and earlier) defines layers that are electrically equivalent

viaLayers (leEquivalent in version 4.3.4 and earlier) defines layers used for vias and the layers they connect

Also check that the layer properties were set when you made the connection.

Incomplete Nets Command Does Not Recognize Connected Pins and Nets

If a pin is connected to a net but has the lxBlockExtractCheck property on it, the incomplete nets command does not recognize that the pin is connected.

If a layer you use for pcells is not listed in the technology file in thelxExtractLayers list, the incomplete nets command does not recognize incomplete nets noted on that layer.

Furthermore, the probe code does not highlight any layer that is not listed in the technology

file in thelxExtractLayers list.

Markers for Nonexistent Overlaps and Shorts Appear

If there are markers for nonexistent overlaps and shorts in the layout, make sure that the appropriate layer was active when the path was created.

If this does not fix the problem, make sure that the connectivity information

(lxExtractLayers and lxNoOverlapLayers) and layer information (equivalentLayers and viaLayers) are set correctly in the technology file.

Virtuoso XL Layout Editor User Guide

Troubleshooting Problems in the Virtuoso XL Layout Editor

Path Ends Not Accepted

If the software rejects the final segment of a path or wire connection and displays the following message:

First or last segment of created path has length less than or equal to half the path width.

Press Return to end a path instead of double-clicking the mouse (do not double-click to end a path).

or

Set the layout window Design – Options – Display command to a snap mode other than x-first or y-first.

When you use the x-first or y-first snap modes, the double-click often makes a notch in the path, which triggers the error message and can cause errors in mask layout.

Notch

Placement and Routing Do Not Run

Virtuoso XL does not let you place or route the elements of a design unless you have defined which layers of your layout design are conducting layers.

Virtuoso XL Layout Editor User Guide

Troubleshooting Problems in the Virtuoso XL Layout Editor

If you try to place or route your design before defining the conducting layers, you get an error message like this.

Virtuoso XL

There are no ‘lxExtractLayers’ defined in library ‘cmos_test’.

To get Virtuoso XL connectivity, you need to update your technology file.

Close

Define the layers you want to be conducting layers aslxExtractLayers in the lxRules class of the technology file.

Virtuoso XL Does Not Recognize Physical Vias

If you have an existing design in which Virtuoso XL does not recognize physical vias, you need to add a property with name = “function”, value = “via” to the master cellview of the via or to the component description format (CDF) for via layout.

Moving Software Executables To a New Location

If you move software executables to a different location other than specifiied by manufacturing, the Virtuoso custom placer may take longer to start because it will be searching for the executable.