Pin Location Constraints
“LOC” constraint used to locate pins:
- From a Schematic attach the attribute “LOC=P12” to the pins you wish to lock down
- I/O constraint based on net name in the .UCF file
NET IOBLOCK/DATA0_IN LOC=P12;
- I/O constraint based on the instance name in the .UCF file
INST IOBLOCK/DATA_IN_PAD LOC=P12;
2.1i produces a .PAD file. Design Manager provides a utility to translate the .PAD file to a .UCF file that contains the pin assignments. In the Design Manager, select the ‘Design’ menu, click on ‘Lock Pins’. This will generate the ucf file. However, the utility will always assume the I/O net name is the same as the IOB name in the NCD (not necessarily true if you use a BLKNM on the I/O. See solution #3534.