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AR# 10865

3.1i Virtex PAR - The router has changed so that backbone resources are always used when the USELOWSKEWLINES constraint is assigned to a net.


Keywords: USELOWSKEWLINES, skew, backbone, clock, constraint, router, routed, routes

Urgency: Standard

General Description:
In the past, the router would sometimes move nets off low-skew backbone resources in an attempt to meet timing constraints, even though the net was constrained to use these resources with the USELOWSKEWLINES constraint. This will no longer occur.

NOTE: This issue affects the Virtex, Virtex-E and Spartan-II device architectures.


This change is available in the latest 3.1i Service Pack, available at:
The first service pack containing the change is 3.1i Service Pack 8.
AR# 10865
Date Created 08/29/2007
Last Updated 10/21/2008
Status Archive
Type General Article