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AR# 23645

8.2i Virtex-5 DRC - "ERROR:PhysDesignRules:1492 - Incompatible programming for comp CFGLUT5_O6_OBU (Incorrect)"


The DRC check for compatible LUT5 and LUT6 configurations does not handle shift registers correctly, leading to a false DRC error:

"ERROR:PhysDesignRules:1492 - Incompatible programming for comp CFGLUT5_O6_OBUF.

The pair of luts SLICEM_A5LUT and SLICEM_A6LUT must have a compatible

equation, lower bits must be programmed the same. The SLICEM_A5LUT hex

equation is <O5=0x00000180> and the SLICEM_A6LUT hex equation is



This problem has been fixed in the latest 8.2i Service Pack available at:

The first service pack containing the fix is 8.2i Service Pack 1.

AR# 23645
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article