UltraScale Architecture SelectIO Resources User Guide (UG571)

Document ID
Release Date
1.14 English

VREF_CNTR is an attribute specific to the receiver VREF scan feature in HP I/O banks. It is used with the HPIO_VREF UNISIM primitive.

The valid values for VREF_CNTR attribute are:

FABRIC_RANGE1 (POD standards)

FABRIC_RANGE2 (other applicable standards)

FABRIC_RANGE1 is used with the POD standards and the FABRIC_RANGE2 is used with the other applicable standards when the receiver VREF scan feature is invoked.

The VREF_CNTR attribute should be set in the UNISIM instantiation. Refer to the UltraScale Architecture Libraries Guide (UG974) [Ref 5] for more information.