Creating a PR Boundary

A placement and routing (PR) boundary is the boundary of a block for place-and-route applications. In a top-down design flow, it is commonly passed down to constrain the area in which the block’s contents are placed. Any shape or instance created for the block should be enclosed within the PR boundary. In a bottom-up design flow, a PR boundary is used to indicate the primary extent of the block’s contents. For cell placement that is directed by sites in a row object, the PR boundary determines the aspect of the cell that must align with the site. Only one PR boundary is allowed per cellview.

When you create or edit a PR boundary, to prevent instances from being placed off the grid, the snap period is taken into consideration when the following conditions are met:

• The snapPatternIndexSnappingLayers environment variable is set to t.
• The snapGridPeriod snap period constraint is defined for a global grid.
• The leSnapPatternSnappingHorizontalGridDetail or leSnapPatternSnappingVerticalGridDetail property is defined for instances.

To create a PR boundary:

1. In the layout window, choose Create – P&R Objects – P&R Boundary.
2. Press F3 to open the Create P&R Boundary form.
   If the visibility setting of P&R Boundary in the Objects panel in the Palette assistant is turned off, a dialog box appears with the option to set the PR boundary to visible and proceed with the boundary creation. When you click Yes, P&R Boundary is set to visible in the Objects panel.
3. Select Create as ROD Object if you want to create the PR boundary as a ROD object. The Name field becomes editable, allowing you to change the name from the default.
4. Use the Define Halo button if you want to create a halo blockage for the PR boundary.
5. From Create Method choose a method and create the PR boundary:
   • From Selected Set: Select objects on the canvas to add to the selected set. Once you have selected the objects, click the Apply button to create the PR Boundary.
   • Rectangle: Specify a rectangle area on the canvas for the boundary. The Apply button and Snap Mode list are grayed out when using this method.
   • Polygon: Select a snap mode and specify a polygon area on the canvas for the boundary. The Apply button is grayed out when using this method.

Related Topics

Create P&R Boundary Form

Blockage Halos

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