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AR# 32533

11.1 Spartan-3A Router - Known Issue where Hold Time router is not able to find the solution that the 10.1 router used


My design worked fine with ISE version 10.1, but now it fails with a single Hold Time violation when I run it with version 11.1. The logic involved in the error has not changed. Why is the router unable to fix this Hold Time violation?


A new check in the Hold Time router was found to have caused this 11.1 regression. A successful route that was used in 10.1 is now being rejected by the router because the check is overly pessimistic.  


This problem will be fixed in ISE version 11.2. Meanwhile, it is possible to use a Directed Routing (DIRT) constraint to force the use of the successful routing previously used by version 10.1.

AR# 32533
Date Created 04/21/2009
Last Updated 05/23/2014
Status Archive
Type General Article