RE: Cinematronics sound board behavior...

G'day Zonn and folks,

Had I known you wanted to see/borrow the Demon boards, I would have brought
them down with me to San Diego last month. I have no problem with folks
reverse engineering these boards as long as I get them back in a few weeks.

                      Steve Ozdemir
                      sozdemir@att.com

-----Original Message-----
From: zonn@zonn.com [mailto:zonn@zonn.com]
Sent: Wednesday, June 23, 1999 12:11 PM
To: vectorlist@mcfeeley.cc.utexas.edu
Subject: Re: Cinematronics sound board behavior...

On Tue, 22 Jun 1999 17:35:44 -0700, you wrote:

>16Mbytes is quite a lot of space though-- even uncompressed. Almost 13
>minutes of 22Khz sample rate mono-8 bit... Could record a pretty long loop
>for that Star Castle droning with that! (I was just thinking of using 8
bit
>samples and mixing them into a 10 or 12 bit word to toss at the DAC)
>Particularly since most fx are going to be a few hundred milliseconds--
>probably only 10-20K bytes. I doubt even *all* the Cinemat games have more
>than 100 unique sounds... Probably more like 50-60?

I think you could do a real decent job of building a sound board just
using samples.

There are a couple of tricky things you'll have to do on a couple of
boards, but they're just tricky, not hard.

As part of getting the samples for Neil (and Retrocade), I've had to
reverse engineer the sound cards.

For each sound card I've written up a spec sheet describing the
hardware in the kind of detail needed to emulate the card. (How the
shift register(s) work, the polarity of all sounds strobes, whether
the sounds must be "looped" or just played once when strobed, the
formulas needed to convert values given from the CCPU to frequencies
to be played, etc.

And to take it step farther I've written a snippet of "C" code for
each board, that would emulate the sound board. Basically if your
Scenix code reads the 6 bit parallel port of the CCPU, and then calls
a routine called 'updateSounds( int outReg)', the code will show you
just what you need to do to emulate the sound card. When to play a
sample, when to "loop" a sample, when to turn off "looping", etc.

Your job "Jim", should you choose to accept it, would be to focus on
playing samples, mixing, looping, etc. and how to fit all the code
into the Scenix code space (you might want a "normal" processor like
an 8051 or something as the controller that triggers the Scenix as the
audio mixer/player.). -- This message will self destruct in 60 seconds
in a big blue screen of death. [Unless your running Linux!]

I've worked out all the interface stuff for:

   Armor Attack
   Rip Off
   Solar Quest
   Space War(s)
   Star Castle
   Star Hawk
   Sundance
   Tailgunner

And have full spec & code snippet write up's (and samples) for Rip
Off, Solar Quest, Armor Attack, Star Castle and Tailgunner, and work
continues...

The two sound cards I don't have are Demon and Barrier. I have the
doc's for Barrier, so I can do the write up's, add a driver to
"CSXOR.EXE -- the Cinematronics Soundboard Exorcisor" but I can't get
samples without an actual card.

Demon will have to be reversed engineered by trial and error. The
CSXOR software should make that easier -- I sure hope there are no
shift registers being emulated by that Z-80! (This assumes Steve O.
will part with the card for a few weeks [again!], when I'm ready for
it! :^)

-Zonn
Received on Wed Jun 23 16:41:02 1999