Virtuoso Schematic Composer User Guide

Creating Schematics

Adding Instances by Rows and Columns (an Array)

To add an array of a single instance using rows and columns, do the following:

1.Choose Add – Instance.

The Add Instance form appears.

2.In the Library, Cell, and View fields, specify the cellview of the instance.

You can also click on the Browse button to assist you in finding the cellview you want to add.

If you do not add instance names in the Names field, the system generates default instance names prefixed with the letterI.

3.Fill in the Rows and Columns fields.

4.Move the pointer into your cellview.

The first instance appears, attached to the pointer.

Virtuoso Schematic Composer User Guide

Creating Schematics

5. Place the first instance by clicking the mouse.

6.Drag the mouse vertically and click on a location for the first instance of the second row. The rest of the instances follow the cursor.

7.Drag the mouse horizontally and click on a location of the first instance of the second column.

Virtuoso Schematic Composer User Guide

Creating Schematics

The rest of the instances follow the cursor.

First instance of the second column

The Add – Instance is modal and continues to prompt you to add another instance. To stop generating instances, press the Esc key, press Control-c, or choose another command.

Virtuoso Schematic Composer User Guide

Creating Schematics

Adding Instances Using an Iterative Expression

Instance iteration is a compact way of displaying repeated instances of a symbol in your schematic. It is particularly useful in bus-type or data-flow architectures that have identical structures to handle each bit on the bus.

To save space in your design window when you need to add several instances of the same type, you can express multiple unique names with an iterative expression. For example, A<0:3> generates one graphic representing four instances: A0, A1, A2, and A3.

Using iterated instances not only saves space in your design, it makes your design easier to read.

To add instances using an iterative expression, do the following:

1.Choose Add – Instance.

The Add Instance form appears.

2.In the Names field, type a name usingiterative expression format.

Virtuoso Schematic Composer User Guide

Creating Schematics

The following schematic shows four instances: I0, I1, I2, and I3. Compare this schematic with the following schematic showing iterated instances:

The following schematic shows one latch iterated four times: I<0:3>. Compare this schematic with the previous schematic showing four individual instances.

I<0:3>