When I use a PULLDOWN or PULLUP constraint on an I/O in my lower-level partition, the following error occurs in MAP:
"ERROR:Pack:1107 - Unable to combine the following symbols into a single IOB component:
BUF symbol "IBUF" (Output Signal = IBUF)
PAD symbol "PAD" (Pad Signal = PAD)
PULL symbol "PAD_PULLDOWN" (Output Signal = PAD)
Symbol IBUF is not in the same Partition as symbol PAD_PULLDOWN. Symbol IBUF belongs to Partition /inst and symbol PAD_PULLDOWN belongs to Partition /top."
Why does this error occur and how do I resolve it?
This issue is fixed in the 11.1 IDS release.
To avoid this issue in previous tools, instantiate the PULLDOWN/PULLUP primitives in the same level of hierarchy as the buffer.
For information on how to instantiate the Verilog and VHDL primitives, please refer to the Libraries Guide.