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Freeing the DMAThere is a way to have a completely bitplane-DMA-free display.
The demo 'Roots' is the one that uses it in rotator/distorter part
with 3x3 pixel display. If you turn off sprite DMA while the sprite
is shown, i.e. between sprite's start and stop boundaries, DMA stops
updating sprite DAT registers, but sprite is kept shown. While sprite DMA is
off, whole sprite is filled with SPRxDAT's contents. It's the only case,
I'm aware of, when you can see anything on screen (i.e. fill whole
screenwith a pattern), while the chipmem bus is completely free.
=)
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