I just started FPGAs. I know that Vref is designed for I/O Banks specially needed for some I/O standards or weak keeping. If I dont need them should I ground these pins or leave them floating( not connected)?
EDITION: specifically I mean XC2S100 in Spartan II group.
Best Answer
I believe you only need to connect to the Vrefs on the bank with your single input.
Here is a quote from the Xilinx web site: