From: Gideon Zweijtzer (gideonz_at_dds.nl)
Date: 2003-07-06 18:40:44
Spiro wrote:
> In fact, I really doubt a breaking charrom would influence
> the displaying of sprites without affecting the 6510 in any
> way - the only way I see the charrom could influence the
> sprites is in that it "shortens" some data or address bus
> pins, but in this case, even the 6510 would not be able to
> see anything useful.
>
> What I see as possible candidates (the list is not complete,
> there might be other things, too):
>
> - the VIC-II itself
> - the PLA
> - the CIA#2 (which generates the address bus lines A14 and
> A15 for the VIC).
I think the CIA#2 is not a candidate, because changing the address lines
A14 and A15 to the VIC-II does not cause sprites to appear, as they are
being turned off in the startup routine of the C-64. It is more likely
that some writes to memory also reflect in writing registers of the
VIC-II, and hence I think it is the PLA.
Gideon
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