From: Marko Mäkelä (marko.makela_at_hut.fi)
Date: 2005-01-22 21:59:54
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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