2 interlace modes are available:
* In interlace sync mode, the same information is painted in both fields to enhance readability. In this mode, reprogramming the CRTC is not necessary
* 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]]
* [[Media:hd6845.hitachi.pdf|HD6845S (Hitachi)]] aka Type 0
* [[Media:UM6845-UMC.pdf|UM6845 (UMC)]] aka Type 0
* [[Media:Um6845r.umc.pdf|UM6845R (UMC)]] aka Type 1. In this document, the figure 7 describing the "Interlace Sync and Video" mode is incorrect
* [[Media:Mc6845.motorola.pdf|MC6845 (Motorola)]] aka Type 2 [[Media:Mc6845.pdf|Other datasheet version]]
* [[Media:CPC_Plus_Asic_Schematic.GIF|AMS40489 (Amstrad)]] aka Type 3