d50e51ada6
The IBUFDS primitives in ad9484_interface_400m.v hardcoded LVDS_25 and DIFF_TERM TRUE, which overrode XDC constraints. On the XC7A50T (Bank 14 VCCO=3.3V), this caused a BIVC-1 DRC error: LVDS_25 requires VCCO=2.5V, conflicting with adc_pwdn (LVCMOS33, VCCO=3.3V) in the same bank. Changes: - ad9484_interface_400m.v: IBUFDS parameters changed from LVDS_25/DIFF_TERM TRUE to DEFAULT/DIFF_TERM FALSE, delegating control to XDC per target - xc7a50t_ftg256.xdc: Re-enable DIFF_TERM TRUE (safe now that RTL does not hardcode LVDS_25), update DRC Fix History with correct root cause