I am a newbie and I need rules to assign pins to FPGA. I would imagine some,

1. Group signals that are natually related, and assign them to the same I/O
bank/side of the FPGA;
2. Let the software to assign pins, then fix some pins according to the
automatic assignment, then let the software run again. Do this iteratively
for several times.

What is your experience? Suggestions are welcomed.

vax, 9000