* In interlace sync and video mode, alternating lines are displayed in the even and odd field to double the resolution. In this mode, it is necessary to reprogram the CRTC as if we were building a frame of 624 lines. The 625th line is managed automatically by the CRTC
[[File:CRTC Interlace modes.png]]
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=== Vertical Displayed (R6) ===
On CRTCs 0/1/2, the condition C4=R6 is considered immediately to activate the VBORDER.
On CRTCs 3/4, the R6 test is done only at new character line start. The update of R6 during the character line is therefore not considered.
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