MSS DDR VREF (PolarFire SoC Only)

Bank 6 is unique as it has two internal VREF generators. These VREF generators have separate and different VREFs, one for the CA bus and the other for the DQ bus. When both VREFs are used internally, the values are same, which is 50% of VDDI for that bank. If it is desired to have a unique voltage for the DQ bus, any of the I/O’s in that bank can be selected to provide an external VREF voltage. Typically, both VREFs are internal and the same. It may be desirable to provide external VREF for DQ depending on terminations, or simply having the ability to monitor that voltage.