Commodore Amiga A2000 - Page 67

d. Specify resolution:
o Low resolution:
* 320 pixels in each horizontal line.
* Clear bit 15 in register BPLCON0 (HIRES).
o High resolution:
* 640 pixels in each horizontal line.
* Set bit 15 in register BPLCON0 (HIRES).
e. Specify interlaced or non-interlaced mode:
o Interlaced mode:
* 400 vertical lines for NTSC, 512 for PAL.
* Set bit 2 in register BPLCON0 (LACE).
o Non-interlaced mode:
* 200 vertical lines for NTSC, 256 for PAL.
* Clear bit 2 in BPLCON0 (LACE).
2. Allocate Memory. To calculate data-bytes in the total bit-planes, use the following
formula: Bytes per line * lines in playfield * number of bit-planes
3. Define Size of Display Window.
o Write start position of display window in DIWSTRT:
* Horizontal position in bits 0 through 7 (low-order bits).
* Vertical position in bits 8 through 15 (high-order bits).
o Write stop position of display window in DIWSTOP:
* Horizontal position in bits 0 through 7.
* Vertical position in bits 8 through 15.
- Playfield Hardware 58 -