SLVUAW9C September 2016 – February 2020 UCD90320
Margining can be enabled with the Input Pin selected by this byte (see Table 66). The pin is ignored if the value of this byte is 0.
When this pin is asserted, all rails with margining enabled (see Section 10.35) are put in a margined state (low or high).
NOTE
If a valid pin is selected with this byte, a valid pin must be selected with the MRG_LOW_nHIGH byte as well.