MAP issues the following error:
"ERROR:Pack:679 - Unable to obey design constraints (LOC = Y4) that require the combination of the following symbols into a single I/O component:
PAD symbol "strtstop.PAD" (Pad Signal = strtstop)
BUF symbol "strtstop_IBUF" (Output Signal = strtstop_IBUF)
PAD symbol "reset.PAD" (Pad Signal = reset)
More than one pad symbol. Please correct the design constraints accordingly. Problem encountered during the packing phase."
In this case, the pack error occurred because two different signals were incorrectly assigned to the same pad location.
To avoid this error, assign each signal to a separate pad.
Check the pin locks in your UCF. If there is an asterisk (*) character in a signal's name, it will be interpreted as a wild card character, and this will result in multiple signals being locked to a single pad.