If the Read DBI option is selected for DDR4/LPDDR4, the DBI input pin is
calibrated by writing a 101010... pattern into the DRAM,
enabling the read DBI functionality, and reading back the pattern from the DRAM. The
DRAM sends the data back as 11111111, (or 00000000_00000000 for LPDDR4), but the DBI pin itself has
the 101010... pattern, that is used to calibrate the DBI
input pin itself.