Weighting and color-coding nets

Layout places a higher priority on keeping higher-weighted nets and their components together during placement. In Layout, nets are weighted on a linear scale from 0 to 100.

To weight and highlight nets

1 Choose the spreadsheet toolbar button, then choose Nets. The Nets spreadsheet appears.

2 Double-click in the Net Name cell that corresponds to a net whose weight you want to change, or that you want to highlight. The Edit Net dialog box appears.

3 To change the weight for a net, type in a new weight in the Weight text box, then choose the OK button or use the scroll bar at the left of the text box to change the number, then choose the OK button. The new number shows in the Weight column of the spreadsheet.

4 To highlight a net, select the Highlight option in the Edit Net dialog box, then choose the OK button. The net shows in the highlight color.

To color-code a net

1 In the Nets spreadsheet, select the net(s) to which you want to assign a color.

2 From the pop-up menu, choose Change Color, then select a color from the color palette that appears.

Checking gate and pin information

A package is the electronic gate and pin information associated with a component (as opposed to a footprint, which is the information regarding the physical characteristics of a component). The information in the Packages spreadsheet is used to determine whether you can swap gates between identical components or only within a component, and how the gates are arranged within a part.

To check gate and pin information

1 Choose the spreadsheet toolbar button, then choose Packages. The Packages spreadsheet appears.

2 Verify that the following information in the spreadsheet is correct, then close the spreadsheet.

Securing preplaced components on the board

If your design has components or footprints that were placed at the schematic level or as part of the template, you should ensure that they were placed properly before you begin placing additional components. Preplaced components may include connectors, mounting holes, memory arrays, predefined circuits, alignment targets, and components that must be placed in specific locations due to mechanical or temperature restrictions. After you are satisfied that the preplaced components are properly placed, you must affix them to the board using the Fix or Lock commands. Otherwise, they may be moved inadvertently when you are placing other components.