Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

To verify that all connections are made in the layout as specified in the schematic, use an

verification product to run a layout versus schematic (LVS) check on the completed design.

Note: For hierarchical connectivity to work for pcells, the connectivity must be defined on the shapes within the pcell. You can assign connectivity for the pcell shapes by descending into the pcell and using the Connectivity – Add Shape to Net command. For the non-pcells, you can assign connectivity interactively using the Connectivity – Assign Nets command or using Cadence® SKILL functions.

The connectivity extractor recognizes connectivity only if all the shapes on a net have connectivity information. Otherwise, it reports incomplete nets even though the router reports that the design is 100% routed.

Do not use mosaics to make connections in Virtuoso XL. the connectivity extractor cannot use them.

Pseudo-Parallel Connections

Pseudo-Parallel connects are created by using the Connectivity – Define Pins – Pseudo Parallel Connect command.

Selecting Layers

To select the layer you want to use to connect design components, do this.

Select a layer in the Layer Selection Window (LSW).

Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

The layer you select appears in the current layer display.

Current layer display

Note: The layout window Create – Path command automatically changes the current layer to the layer of the first pin you select to start the path.

Changing Layers

Another way of changing the current layer display is by using the Change Layer option from the Create Path form.

1.Select Create - Path.

2.Toggle on the Change Layer and Switch Layer Purpose options.

3.Move your cursor into the layout window and click on a shape.

Notice that the LSW updates the current layer to be the same layer as the shape that you clicked on. The purpose of the layer is drawing, which is the first purpose listed in the

Layer Purpose Order.

4.Change the Layer Purpose Order in the Create Path form to net pin drawing.

5.Click on a shape in the layout window and notice that the current layer is the same layer as the shape that you clicked on with a purpose of net.