Impossiblator 3 bus trick

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Impossiblator 3 bus trick

Post by pixel »

http://www.pelulamu.net/viznut/blog/2007-08-10/

Wow... I mean WOW! I mean... seriously... I... I... :shock:

Can't obsess over this right now, so does anybody have a clue what's going on there? Neither screen or character memory seem to be unconnected. :( Imagine the games one could make with this... :twisted:

EDIT:

O.K. as usual I should've gotten myself a teddy bear to ask it before posting. It must be half unconnected, half connected character memory. Still odd that this stuff is hardly used anywhere.
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Mike
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Re: Impossiblator 3 bus trick

Post by Mike »

In 2006 we had a fairly long thread running, 'VIC-I anomalies in emulation', where carlsson and I set up some routines to let VIC read the last byte put on the data bus by the CPU (see the discussion beginning on the bottom of the third page).

We didn't get to the results hoped for (especially, an early attempt to realise a 208x256 mode), because the effect only really works for internal RAM. Also, there are two different behaviours, some boards seem to mask in the data (OR), other look like they mask out (AND). In any case it is something which cannot be relied upon outside the context of a demo.

And, instead of hunting daydreams at that time, I decided to put work into something realisable, and MINIGRAFIK was the result. ;)
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