VDC register set:
| |
|
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| $00 (R/W) | HT |
Horizontal Total (Clock cycles per rasterline - 1) |
| $01 (R/W) | HD |
Horizontal Displayed (Visible character columns) |
| $02 (R/W) | HP |
Horizontal Sync Position |
| $03 (R/W) | VW/HW |
Vertical Sync Width (rasterlines) |
Horizontal Sync Width (characters+1) |
| $04 (R/W) | VT |
Vertical Total (Character rows per frame - 1) |
| $05 (R/W) | VA |
unused ¹ |
Vertical Total Adjust (Rasterline count finetuning) |
| $06 (R/W) | VD |
Vertical Displayed (Visible character rows) |
| $07 (R/W) | VP |
Vertical Sync Position |
| $08 (R/W) | IM |
unused ¹ |
Interlace mode |
| $09 (R/W) | CTV |
unused ¹ |
Rasterlines per character row - 1 |
| $0A (R/W) | CM/CS |
unused ¹ |
Cursor mode |
Cursor start |
| $0B (R/W) | CE |
unused ¹ |
Cursor end |
| $0C (R/W) | DS |
Display Start Address (A15-A8) |
| $0D (R/W) | DS |
Display Start Address (A7-A0) |
| $0E (R/W) | CP |
Cursor Address (A15-A8) |
| $0F (R/W) | CP |
Cursor Address (A7-A0) |
| $10 (R/W) | LPV |
Vertical light pen position |
| $11 (R/W) | LPH |
Horizontal light pen position |
| $12 (R/W) | UA |
VDC memory update address (A15-A8) |
| $13 (R/W) | UA |
VDC memory update address (A7-A0) |
| $14 (R/W) | AA |
Attribute address (A15-A8) |
| $15 (R/W) | AA |
Attribute address (A7-A0) |
| $16 (R/W) | C?H |
Character width including gap (pixels - 1) |
Character width (pixels) |
| $17 (R/W) | CDV |
unused ¹ |
Character height (rasterlines - 1) |
| $18 (R/W) | VSS |
Fill/Copy |
Reverse |
Blink freq |
Vertical smooth scroll |
| $19 (R/W) | HSS |
Bitmap |
Attributes |
Gap fill |
Pixel clock |
Horizontal smooth scroll ³ |
| $1A (R/W) | FG/BG |
Foreground color |
Background color |
| $1B (R/W) | AI |
Address increment per row |
| $1C (R/W) | CB |
Character base address (A15-A13) |
RAM-Type |
unused ¹ |
| $1D (R/W) | UL |
unused ¹ |
Underline scan line |
| $1E (R/W) | WC |
Block copy/fill word count |
| $1F (R/W) | DA |
Data register |
| $20 (R/W) | BA |
Block copy source address (A15-A8) |
| $21 (R/W) | BA |
Block copy source address (A7-A0) |
| $22 (R/W) | DEB |
Display enable begin |
| $23 (R/W) | DEE |
Display enable end |
| $24 (R/W) | DRR |
unused ¹ |
DRAM refresh cycles per rasterline |
| $25 (R/W) | |
HSYNC ² |
VSYNC ² |
unused ¹ |
