Re: [stella] Cartridge dumper

Subject: Re: [stella] Cartridge dumper
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Thu, 9 Jan 2003 22:42:33 +0100
Hello Adam,

> It doesn't look like that code reads the music data.  Or did I miss
> something?

The music is generated by the game as it is running. The DPC provides
three squarewave channels. The game tells the DPC which frequency the
tones should have at any given time, and the DPC combines that into
single bytes of sample data. The game then keeps reading the sample data
from the DPC and sends it quickly to one of the TIA volume registers.
That way a 15Hz wave signal is generated.

There is no need to read any special music data to make the ROM
play on an emulator. The emulator knows how to generate the sample
data just like the DPC does, so the program code in the ROM is
enough to emulate Pitfall 2.

Ciao, Eckhard Stolberg

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