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
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