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AR# 9958

3.1i Floorplanner - "ERROR:Pack 276 - Unable to follow packing constraints specified by the floorplanner..."/"ERROR:Pack 679 - Unable to obey design constraints..."


Keywords: Floorplanner, pack, 276, 679, packing, constraints, unable, obey, illegal, physical, site, global, pads, Virtex

After I floorplan my design, the following errors occur:

"ERROR:Pack:679 - Unable to obey design constraints (LOC = B14) which require the combination of the following symbols into a single I/O component:
PAD symbol "RdEnFifo2_N.PAD" (Pad Signal = RdEnFifo2_N)
BUF symbol "RdEnFifo2_N_obuf" (Output Signal = RdEnFifo2_N)
The symbol RdEnFifo2_N.PAD has a constraint (LOC=B14) that specifies an illegal physical site for the component. Please correct the constraint value. Please correct the design constraints accordingly."

"ERROR:Pack:276 - Unable to follow packing constraints specified by the floorplanner. Refer to the error messages above to determine why the floorplan constraints are not followed. The floorplan may need to be modified."


These errors occur because Floorplanner places illegal I/O constraints to global sites on the design. This happens to unconstrained I/O, which should not be placed on global sites. If the Floorplanner is opened and these illegal I/O constraints are seen in the design, saving a new MFP file will result in a MAP error.

To work around this issue, manually change the illegal constraints in Floorplanner and re-save. After the new FNF and MFP files are saved, the correct placements will take effect.
AR# 9958
Date Created 08/21/2007
Last Updated 06/01/2009
Status Archive
Type General Article