PUDC_B pin is floating this pin If PUDC_B in 7 series or Zynq devices is left floating on the board, the behavior of the SelectIO pins will be unknown.it could be that the pin will be pulled up or 3 states. PUDC_B controls the behavior of the Selectio pins.......

Answers 59958 and ug865 see table 1-5 ug470 see Table 2-4