To set interlaced or non-interlaced mode, you write to bit 2, LACE, in register BPLCON0:
Interlaced mode write 1 to bit 2.
Non-interlaced mode write 0 to bit 2.
As explained above in "Setting the Number of Bit-Planes," bits in BPLCON0 are not
independently set.
The following example shows how to specify high-resolution and interlaced modes.
MOVE.W #$A204,BPLCON0+CUSTOM ; Write to it
The example above also sets the following parameters that are also controlled through
register BPLCON0:
o High-resolution mode is enabled.
o Two bit-planes are used.
o Hold-and-modify mode is disabled.
o Single-playfield mode is enabled.
o Composite video color is enabled.
o Genlock audio is disabled.
o Light pen is disabled.
o Interlaced mode is enabled.
o External resynchronization is disabled.
The amount of memory you need to allocate for each bit-plane depends upon the
resolution modes you have selected, because high-resolution or interlaced playfields
contain more data and require larger bit-planes.
- Playfield Hardware 45 -
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