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Blitter mode
The blitter is a component of the Amiga that can eciently transfer large
sections of data in memory on behalf of the CPU, freeing the CPU to do other
things. The behaviour of THEA500 Mini blitter can be modied by setting the
Blitter mode to one of three modes:
Normal In this mode the THEA500 Mini blitter will behave exactly the
same as an original Amiga blitter. This can sometimes cause
image corruption when older games are run at a CPU speed
higher than they were written for (see the Wait mode for more
details).
Wait Some older programs, usually written for the Amiga 500, assume
the blitter will have nished what it was doing before they next
need it. However, when run on an Amiga with a faster CPU (such
as the A1200) this is often not the case and new commands are
sent to the blitter before it has nished processing the last. This
will usually lead to image glitches.
Setting the Blitter mode to Wait will pause the CPU when it
attempts to send new commands to the blitter before the current
commands have completed.
Immediate This puts the blitter into turbo mode where commands complete
almost immediately, so the CPU does not need to wait before
sending new commands. This can increase performance, but at
the risk of breaking some programs that expect the blitter to take
a certain amount of time.
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