From: David Wood (jbevren_at_starbase.globalpc.net)
Date: 2005-01-22 22:56:23
Actually, I'm betting the clip is to pick up the 12v (or 9v?) from the other
sid. ;-)
You can get your chipselect off the cartport, even though it wouldnt be in
the D4xx range.
-jbev
On Sat, 22 Jan 2005, Marko [iso-8859-1] Mäkelä wrote:
> On Sat, Jan 22, 2005 at 10:59:07AM -0600, Glenn Holmer wrote:
> > I've got one of Mark Dickenson's hand-built C64 cartridges with the
> > second SID chip. It gets it power from a clip that goes on one
> > of the chips inside the machine, but I can't find the docs to know
> > which one. Anybody know where I can find out about this?
>
> I'm not familiar with that product. What are the dimensions of the
> clip? How many pins does it have, or how many pins does an IC have
> where it fits physically perfectly?
>
> Are you sure that it's for power supply? The cartridge port has four ground
> lines and two +5v lines, and I'm pretty sure that the cartridge port connector
> is not the bottleneck; the mains power supply is. How many wires are
> running from the clip, and where do they end up on the cartridge?
>
> I'd guess that the clip is for the PLA or one of the 74xx chips that decodes
> the addresses for the I/O space. Does the documentation specify how the
> second SID can be addressed? If the chip is sitting somewhere between
> $de00 and dfff, then you can ignore this suggestion.
>
> One more guess: maybe the cartridge requires some timing signal that is
> not available on the cartridge port? Or maybe it's the audio in signal.
> That one should not need to be connected.
>
> Marko
>
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