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Blitter mode
The blitter is a component of the Amiga that can efficiently 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 modified 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 finished 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 finished 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.
