[stella] Pokey

Subject: [stella] Pokey
From: Glenn Saunders <krishna@xxxxxxxxxxxx>
Date: Sat, 18 Oct 1997 11:04:50 -0700 (PDT)

On Sat, 18 Oct 1997 crackers@xxxxxxxx wrote:
> Anyone got any information on how exactly activision implimented the
> pokey chip in the Pitfall][ cart?

There is no Pokey chip in Pitfall ][.  There is a custom chip called the
DPC chip, as it was designed by David Crane (the old programmers were
often also great hardware engineers).  How it generates sound is rather
complicated, and fascinating, but it still is just feeding the existing
2600 sound hardware on the fly.

The DPC chip has other features as well which allow for better graphics. 
How that works is even more complicated, but I think it essentially works
like a math coprocessor of sorts, calculating things automatically that
used to take a lot of cycles to do, hence freeing up cycles that can be
used to have more sprites and color changes and so on.

There is a Pokey chip in 7800 Ballblazer.  How it integrates with the 7800
is a mystery to me, and I don't know if such a beast would work in 2600

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