A case has been seen where MAP failed with the following Internal Errors while writing the NCD file:
"Using target part "4vlx15ff668-11".
Mapping design into LUTs...
Writing file flat_map.ngm...
Running directed packing...
Running delay-based LUT packing...
Running related packing...
Writing design file "flat_map.ncd"...
INTERNAL_ERROR:Pack:pksbatsdesign.c:1610:1.31 - No Xdm objects for
PERIOD=20000.000000 pS HIGH 50.000000% with references:
In general, this error is an indication of a problem in signal correlation during timing specification processing. This particular case has been fixed for 7.1i sp2.
One known source of this problem has been fixed in the latest 7.1i Service Pack available at:
The first service pack containing the fix is 7.1i Service Pack 2.
Another source of this problem has been fixed for version 8.1i and can be worked around by disabling KEEP HIERARCHY attributes during MAP (-ignore_keep_hierarchy).