This information is provided in the event the programmer requires more complex control of the video hardware. Use of this information is strictly at your own risk, as some manufacturers use the entries below for contrasting purposes.
Group | Resister | Index Port | Data Port | Index Value |
CRT Control | Horizontal Total | 3D4h | 3D5h | 00h |
Horz. Display End | 01h | |||
Start Horz. Blanking | 02h | |||
End Horz. Blanking | 03h | |||
Start Horz. Retrace | 04h | |||
End Horz. Retrace | 05h | |||
Vertical Total | 06h | |||
Overflow | 07h | |||
Preset Scan Row | 08h | |||
Max Scan Line | 09h | |||
Cursor Start | 0AH | |||
Cursor End | 0Bh | |||
Start Addr. High | 0Ch | |||
Start Addr. Low | 0Dh | |||
Cursor Location High | 0Eh | |||
Cursor Location Low | 0Fh | |||
Start Vert. Retrace | 10h | |||
End Vert. Retrace | 11h | |||
End Vert. Display | 12h | |||
Offset | 13h | |||
Underline Location | 14H | |||
Start Vert. Blanking | 15h | |||
End Vert. Blanking | 16h | |||
Mode Control | 17h | |||
Line Compare | 18h | |||
Sequencer | Reset | 3C4H | 3C5H | 00h |
Clocking Mode | 01h | |||
Map Mask | 02h | |||
Character Map Select | 03h | |||
Graphics | Set/Reset | 3CEH | 3CFH | 00h |
Set/Reset Enable | 01h | |||
Color Compare | 02h | |||
Data Rotate | 03h | |||
Read map Select | 04h | |||
Mode | 05h | |||
Miscellaneous | 06h | |||
Color Don't Care | 07h | |||
Bit Mask | 08h | |||
Attribute | Palette | 3C0H | 3C0H | 00h - 0Fh |
Mode Control | 10h | |||
Overscan Color | 11h | |||
Color Plane Enable | 12h | |||
Horz. Pixel Panning | 13h | |||
Color Select | 14h | |||
General | Misc. Output | 3CCH | 3C2H | R/W |
Feature Control | 3CAH | 3DAH | R/W | |
Status #0 | 3C2H | read only | ||
Status #1 | 3DAh | read only | ||
Color | Color Address Write | 3C8H | write only | |
Color Address Read | 3C7H | write only | ||
Color Data Register | 3C9H | 3C9H | R/W |
Notes:
1. Registers specified as Read, Write or R/W use addresses listed without indexes. First address is read location, second write.
2. Bit 7 on End Vert. Retrace is write protect for CRT registers at indexes 0 to 7.
3. Bit 4 on Overflow is Line Compare bit 8.
4. Bit 6 on Max. Scanline is Line Compare bit 9.
5. Bit 3 on Status #1 is Vertical Retrace.
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