I have one question on pin not use This pin can be free or is only necessary confing in out pin for prevent the noise?
Regards Franco
That depends a bit on which pins you are thinking about.
Note that the I2C pins (P0.27, P0.28) are open-drain and don't have pull-up/pull-down support.
In the same way, P0.29, P0.30 and P0.31 don't have pull-up or pull-down.