The input buffer (IBUFE3) primitive (shown in This Figure ) is only supported in HP I/O banks. This UltraScale architecture specific primitive has functions similar to the IBUF_IBUFDISABLE with added controls for offset calibration and V REF tuning, along with input buffer disable (IBUFDISABLE). The offset calibration feature is accessed using the OSC_EN and OSC[3:0] ports. The V REF scan feature is accessed using the HPIO_VREF primitive in conjunction with IBUFE3.