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SPI-4.2 v9.1 - NCSim timing simulation does not work with SDF file
NCSim timing simulation does not work correctly with an SDF file. There are data mismatches caused by data going to an unknown "X" state.
To work around this issue, run the simulation without bringing in an SDF file. This issue is scheduled to be fixed in ISE software 12.1.
05/04/2009 - Initial Release
04/07/2010 - Added fixed version