Making Small Modifications to Automatic Placement

This procedure describes how to make small changes to an automatically placed design in order to fix packing or placement problems. A scenario when this might be required is when the automatic placement tools meet timing on all paths except one, and the one path that is failing is due to bad logic placement in the path. Using the Floorplanner you can copy the entire automatic placement to the Floorplan window, and then make the small modifications necessary to fix the timing problems. You can then re-map and place and route the design.

1. Use the Placement window and timing reports to identify problems in the automatic placement.
   
   
2. Select Floorplan Replace All with Placement to copy the entire placed design from the placed design over to the Floorplan window.
   
   
3. Make the changes to the Floorplan window to correct any placement that was causing timing problems in the initial timing analysis.
   
   
4. Select File Save to save the floorplan and generate an MFP file.
   
   
5. Map the design using the newly created MFP file.
   
   
6. Place and route the design to determine if the new placement constraints allows the design to meet the required timing.