Steps:
1. Within the Constraint Manager, go to the Electrical > Routing > Wiring worksheet.
2. In the Schedule column, you can right click your Dsn cell and create a new Electrical Constraint Set (ECS). Notice in the
image below, we have multiple ECSets already declared.
3. Select the drop-down in one of the cells in the Schedule column and you can choose your net topology.
These are the net topology options that are available:
f
Minimum Spanning Tree
f
Daisy-chain
f
Source-load Daisy-chain
f
Star
f
Far-end Cluster
f
(Clear)
Each topology has its own benefits, depending on the application.
4. Once you have set the topology for that ECSet, you can apply it to the appropriate nets found in the spreadsheet under
Electrical Constraint Set > Net > Routing > Wiring.
5. In this example, however, you can also directly apply a net schedule (see below).
Note: Depending on your use case, you can use either constraint sets or a specific rule application as needed, as seen in this
example. However, please use constraint sets as much as possible to catch the majority of cases first before applying
net-specific one-off rules. Using constraint sets modularizes and streamlines your PCB design constraint process and makes
designing more efficient. The constraint set method also reduces the likelihood of errors and forgotten constraints.
Benefit: Improves signal integrity and timing by ensuring critical connections are made efficiently.
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OrCAD X High-Speed Digital Design Guide
