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SUMMARY
The steps for defining a basic playfield are summarized below:
1. Define Playfield Characteristics
a. Specify height in lines:
o
200 maximum for non-interlaced mode.
o
400 maximum for interlaced mode.
b. Specify width in pixels:
o
320 maximum for low-resolution mode.
o
640 maximum for high-resolution mode.
c.
Specify color for each pixel:
o
Load desired colors in color table registers.
o
Define color of each pixel in terms of the binary value that points at the
desired color register.
o
Build bit-planes.
o
Set bit-plane registers:
*
Bits 12-14 in BPLCONO - number of bit-planes (BPU2 - BPUO).
*
BPLxPTH - pointer to bit-plane starting position in memory (written as
a long word).
d. Specify resolution:
o
Low resolution:
*
320 pixels in each horizontal line.
*
Clear bit 15 in register BPLCONO (HIRES).
Playfield Hardware 53
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