>=20
> Texas Instruments used to make the SN76477 and the SN76496.
> These are listed as "sound generators" and were meant to be
> used in video games to produce a variety of sound effects. They
> contained a noise source and various envelope generators.
> The former chip (and maybe the latter) are no longer made, but
> the
> data sheets may be available somewhere. They showed how various
> sounds were synthesized; this might give you some ideas.
>=20
> John Power

This is an interesting subject.  I was looking at the embedinc website =
on their HAL project, and how they use PWM to make all sorts of sounds.  =
It went right over my head, but it gave me ideas to experiment with.

Just the PWM output from this code produces a sound like a motor, sort =
of like the one from Pink Floyd's Welcome to the Machine:

test
        banksel T2CON
        btfss           T2CON,TMR2IF
        goto            $-1
        banksel CCPR1L
        decf            CCPR1L,f
        banksel PR2
        incf            PR2,f
        goto            test

So it got me to thinking that with the proper algorithms and maybe a =
little help from some simple wave shaping components, one could get an =
awful lot of good sounds from a PIC easily. =20

Make the input voltage controlled and then it would be easy to build a =
sonar or IR controlled Theremin, or as another PIC project create a midi =
to control voltage converter.

It also got me to thinking about the difference between using tables to =
produce a wave as opposed to using an algorithm. =20



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=20

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