Hello...I am using XMC4800 microcontroller for EtherCAT application. For my application HIB_IO pins are not required. I am providing an external coin cell battery of 3V to VBAT pin. So my question is, is it safe to just leave the HIB_IO pins non connected? If it is not safe Please tell me whether I should connect a pull down or pull up resistor. Also I have not used some of the GPIO pins. So is it safe to leave them non connected. Please help me to find out.

Thank You