From: Anders Carlsson (anders.carlsson_at_mds.mdh.se)
Date: 2003-01-24 08:25:46
On Fri, 24 Jan 2003, Groepaz wrote:
> uhmz... i would like all (+3k,+8k,+8k,+8k) at once ofcoz .. uhm :/
That memory configuration is normally not available in other environments
than VICE and possibly if you have a very special memory expansion. Since
the video matrix has to be somewhere in $1000-$1FFF (or possibly somewhere
in $0000-$03FF, which is crammed with other stuff anyway), an expansion in
memory in both directions will be quite non-standard and probably useless
in Basic. Only a machine code program could take advantage of it, and I
don't think there are many programs available which will.
Cartridges like Super Expander, Buti Plus and Datatronic's Forth all have
3K RAM built-in. At least with the Super Expander, I think you have to
issue special commands to use it with a +8K or more expansion, or it
automatically discards its internal memory expansion in that case.
While we're into the VIC-20 memory map, what are I/O blocks 2 and 3 for?
The first block maps VIC-I and the VIAs -- is the other two blocks just
mirrors of the first block or dummies which could've been filled by RAM
instead?
--
Anders Carlsson
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