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AR# 10049

3.1i Virtex-E PAR - The router doesn't always use a long line when one is available


Keywords: route, router, long, line, timing

Urgency: Standard

Problem Description: A case has been seen where a timing critical
signal is routed using a string of many hexes when there are two
unused horizontal long lines available in that row. The result is a
net with fanout=1 taking 9.944 ns and missing the timing constraint
by 4.212 ns.

The problem was found to be due to a problem in router cost
calculation specific to the -7 speed grade.


This problem is fixed in the latest 3.1i Service Pack available at:
http://support.xilinx.com/support/techsup/sw_updates. The first
service pack containing the fix is 3.1i Service Pack 3.
AR# 10049
Date 08/19/2002
Status Archive
Type General Article