AR# 10705

3.1i Virtex-II PAR - PAR hangs while routing PWR/GND nets in a Virtex-II design.


Keywords: Virtex-II, PAR, PWR/GND, hang, route

Urgency: Standard

General Description:
When implementing a Virtex-II design that contains both Virtex-II multipliers and
512x32 BlockRAM configurations, PAR may hang while trying to route the PWR
or GND nets.

The problem is related to the fact that in Virtex-II hardware, BlockRAMs and multipliers
share pins. The placer is incorrectly placing BlockRAM and Multipliers in conflicting
locations, which leads to contention over routing resources. The existence of unroutable
connections results in the apparent router hang.


This problem is scheduled to be fixed in the next 3.1i Service Pack available at: The first
service pack that will contain the fix is 3.1i Service Pack 7.
AR# 10705
Date 10/21/2008
Status Archive
Type General Article