If a pad connected to a global buffer (BUFG or BUFGP) is assigned to a nonglobal pad location, MAP issues the following error:
"ERROR: MapLib:93 - Illegal LOC on symbol "clk.PAD" (pad signal=clk) or BUFGP symbol "u1" (output signal=u1), IPAD-IBUFG should only be LOC'd to GCLKIOB site."
Verify that the pad is assigned to a global pad location. This information is available in the data sheet for the device you are using. You can access data sheets at:
This error is often seen when you want to drive a BUFG from a non-GCLKIOB site. The presence of the BUFG causes an IBUFG to be inferred during synthesis, which is incompatible with the non-GCLKIOB site. You should instantiate an IBUF instead.