Pin assignment change problem

Hello everyone

I am using Deo nano fpga and Sam4s Xplained pro kit, where sam4s is i2c master and deo nano is i2c slave.

I am using https://github.com/oetr/fpga-i2c-slave, and I am able made a bridge between them. I can read and write data by SAM4s, without any problem. Now when I am going to use several other i/o s in fpga, i cant assign specific pins. To be more precise, my SAM4s is writing some data to fpga, and read some encoder information from fpga. At the beginning I used random pins to be sure that it is working, and it worked! However, now I am planning to assign pins according to wiring comfort, but it just doesnt work for me. if I change any pins, most the time time the i2c bridge stops working, other thing works at both arm and fpga, seems they dont talk at all if any other pins are going to be changed (not the pin of scl and sda)

I think I am missing some silly things, what is the formal way to change pins in Quartus. All my unused pins are tri stated with weak pull up

Thanks for your answers