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AR# 50698

MIG 7 Series DDR3/DDR2 - Some configurations fail to meet timing due to logic not being placed properly


Version Found: v1.5
Version Resolved and other Known Issues: See (Xilinx Answer 45195).

In some MIG 7 series DDR3/DDR2 configurations, some logic is not being placed within the correct clock region.

This causes excessive net delay going to some of the hard blocks (for example OUT_FIFO).


This is an issue related to the placement algorithm and not to the MIG design itself.

To work around the issue, the user can manually set AREA_GROUP constraints to force the placer to place the logic within the same clock region, or the following environment variable can be set:


For instructions on how to set up an environment variable please refer to (Xilinx Answer 11630).

AR# 50698
Date Created 07/11/2012
Last Updated 08/13/2014
Status Active
Type Known Issues
  • Kintex-7
  • Artix-7
  • Virtex-7
  • MIG 7 Series