Re: [stella] Kool Aid Man compatible detection

Subject: Re: [stella] Kool Aid Man compatible detection
From: Adam Wozniak <adam@xxxxxxxxxxxxxxxx>
Date: Sun, 10 Oct 2004 08:00:57 -0700 (PDT)
Hash: SHA1

On Sun, 10 Oct 2004, Eckhard Stolberg wrote:
> BTW, while you are looking at the TIA schematics, could you
> find out when exactly the audio output is updated? I think the
> TIA changes the audio output twice per scanline, and I'd like to
> know when exactly this happens.

Changes to the registers happen immediately, but you won't hear
the difference until the next audio clock, which is driven off the
horizontal position counter.  So yeah, it'll sound like it updates twice
per scanline.

If you want to know exactly where in the scanline, you can look at the
comparators off the ripple counter on page one of the tia schematics,
in the upper right corner.  (The wired nor values that feed into latches
that drive the audio phase one and two clocks around about grid C5).

Without spending it too much time on it, it looks like changes for the
clocks happen when the horizontal position counter resets, at "late reset
hblank", at "reset h sync" and at "center" (whenever that is), although
I don't know which of those are rising edges and which are falling edges.

- -- 

"Did he get the girl? Oh, yeah. Why do you think he is drinking?"

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