Posted By BobD on 6/11/2008 6:15 AM
Hello,

When I've worked with designs like this in the past, I've found it best to define the floorplan such that the rows flood the entire die area. This can be achieved using Floorplan->Specify Floorplan->Specify By: Die/IO/Core Coordinates and settings all 3 boxes to be the size of the die area. If this approach is taken, then you should be able to create the fences as you desire, because the core area will effectively extend to where the IO cells are placed, and standard cells will not wander off into the IO area because there are fixed IO cells there obstructing the placeable area. I like this approach because it is more consistent with the long-standing First Encounter partitioning default whereby the partition/fence boundary nicely aligns with the standard cell rows vertically and m2 pitch horizontally.

If you'd like to keep the floorplan defined as it is for some reason, you should be able to change the guide/region/fence snapping preference (Design->Preferences->Floorplan) to "Manufacturing Grid". This should allow you to create a fence outside of the core box. I tested this using 7.1.USR2 and see it working. Please post back if you don't see same- there may be a different approach needed in older software versions.

Hope this helps,
Bob