[stella] A quickie...

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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