UM6845:
Bits 7..6 define the skew (delay) of the CUDISP signal(00 = Non-skew ; 01 = One-character skew ; 10 = Two-character skew ; 11 = Non-output).Bits 5..4 define the skew (delay) of the DISPTMG signal(00 = Non-skew ; 01 = One-character skew ; 10 = Two-character skew ; 11 = Non-output).
Bits 3..2 are ignored.
Bits 1..0 define the interlace mode.
Bits 3..2 are ignored.
Bits 1..0 define the interlace mode.
Interlace modes:
[[File:CRTC Interlace modes.png]]