Virtuoso XL Layout Editor User Guide

Using the Virtuoso Custom Placer

Bulk Terminal

Caution

Although the Edit Component Types form will allow you to assign a cell to multiple component types this may lead to confusion and should probably be avoided.

Pin Placement

You use the Place – Pin Placement command and the Pin Placement form to:

■Assign fixed constraints

■Align pins to any boundary edge (supports rectilinear boundaries)

■Assign specific pin ordering for groups of pins

■Place pin groups with any given pin pitch spacing

Pin pitch spacing is center to center.

■Expand/collapse iterated bus pins (Q<7:0> = Q<7>, Q<6>, Q<5>, etc.)

■Handle multiple pins on the same net (just like Virtuoso XL layout editor), gnd.1 gnd.2 gnd.3)

■Report pins and their assigned locations

■Control how pins are displayed in the Pin Placement form.

■Create vertical and horizontal rails.

■Load the pin constraints from a template file.

Note: The Pin Placement form reflectsall pins currently in the design.

When you click Apply in the Pin Placement form, the pins move to the specified locations except the pins which may have been confined to a fence.

Important

If pins are not assigned to an edge and/or location, the pins will be placed anywhere on the prBoundary.

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You can also assign instance pins to rows, by including particular pin instances in a component type. Use the Add Selected Components button in the Edit Component Types form to do this.

Important

Using the Pin Placement form and the constraint manager to constrain pins can result in conflicting and redundant constraints. Pin constraints may be created in either of two ways; use the Pin Placement form exclusively, or use the constraint manager and constraint manager SKILL functions exclusively

Assigning Pins to an Edge

To specify the edge along which one or more pins should be placed,

1. Choose Place – Pin Placement.

Important

A boundary must exist in the layout window. A warning will appear in the CIW indicating that you cannot edit pin placement without a place and route boundary shape. To generate a boundary, use the Design – Gen From Source command.

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The Pin Placement form appears.

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Important

The Pin Placement form displays alignment constraints for pins created in the Pin Placement form for the boundary edge on which the pins are placed, or are supposed to be placed.

2.Select one or more pins in the Pin Name list box.

Click to select a single pin or click and drag to select a range of pins. You can also select pins in the layout window to highlight them in the Pin Placement form.

If you have iterated bus pins, you can choose to expand or collapse the bus by selecting the bus (example: A<7:0>) and clicking the Expand button. This will expand the bus into individual pins, which can then be individually placed with different constraints.

3.You can also select a pin from the layout and have it highlighted in the list box. Select

Link to Layout and click anywhere in the layout window. Select a pin and the pin is highlighted in the list box.

4.Select the Edge cyclic field and specify eitherLeft, Top, Right, Bottom, Any, or As is.

Use the Select edge from layout option to click on any edge on the boundary. You are prompted to select an edge of the boundary. The Edge cyclic field updates to the edge of the boundary that you have just selected.

Note: If the boundary is a polygon then the edges are listed as Edge 0, Edge 1, Edge 2, etc.

5.In the Order text field specify a number You can change the order of the pins by clicking on the Move pins button(s). Use the Swap order option to swap the position of two selected pins.

6.The Vrail and Hrail buttons allow you to rail a pin either horizontally or vertically. The pin must first be placed on a boundary edge and then selected to be railed.

7.Click Apply to apply each pin assignment. Pins will not move to the boundary edge until you click Apply.

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