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Subject: [stella] A quickie... From: Adam Wozniak <adam@xxxxxxxxxxxxxxxx> Date: Sun, 16 Nov 2003 17:57:07 -0800 (PST) |
I'm trying to capture audio from a real 2600 so I can reverse engineer
the taps in the audio linear feedback shift registers in the TIA.
I've tried using the schematics to figure them out, but I get a little
befuddled, and this looks like a fun way to do it anyway.
I've been able to use source from an emulator to figure out what the
4 bit and 5 bit polynomials are, but the emulator uses random numbers for
the 9 bit polynomial and I want to know the real polynomial for an
actual TIA.
So here's what I need (my assembly is rusty, and this outa be quick
for somebody who's set up to do it already):
a 4K binary which does the following:
set AUDV1 to 0
set AUDV0 to 16
set AUDF0 to 32
set AUDC0 to 0
loop forever {
wait 1 second
increment AUDC0
}
This outa give me a binary that will cycle through the sounds, so I can
sample them with a sound card and reverse engineer the polynomials.
Can anyone help me?
--
adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam/pgp.html
Will code for food. http://cuddlepuddle.org/~adam/resume.html
"The dinosaurs are not around today because they did not have a space program."
-- Arthur C. Clarke
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