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AR# 12433

4.1i Virtex-E PAR - Router may overload buffers, leading to underreporting of timing.


Keywords: timing, under, report, overload, buffers, router, TRCE

Urgency: Hot

General Description:
Under certain buffer loading conditions, TRCE underreports connection delays. This causes PAR to finish with the assumption that the design works successfully. As a result of the underreported delays, the chip may not work.


A change was introduced in the first 4.1i service pack so that the router no longer makes connections of the type that lead to underreported timing.

This problem is fixed in the latest 4.1i Service Pack, available at:
The first service pack containing the fix is 4.1i Service Pack 1.
AR# 12433
Date Created 08/29/2007
Last Updated 10/23/2008
Status Archive
Type General Article