Date sent: Fri, 14 May 1999 15:58:53 -0700
From: Steve Lemke <[EMAIL PROTECTED]>
Subject: Re: SndPlaySystemSound inner workings
To: [EMAIL PROTECTED]
Send reply to: [EMAIL PROTECTED]
> >I'm looking at the Palm OS source code, in particular the sound
> >manager. Any call to SndPlaySystemSound eventually calls SndDoCmd.
> >
> >Is this the source code for 3.1?
>
> No, I believe you're looking at 3.0.
>
> >If not, does SndPlaySystemSound in 3.1 work differently?
>
> No, it calls SndDoCmd, too.
>
> >I don't have any device that has 3.1 (too poor to buy
> >a IIIx), but I'm getting feedback from an alpha tester of my software
> >that would indicate that SndPlaySystemSound in 3.1 works differently
> >than in previous versions.
>
> SndPlaySystemSound is basically the same, although SndDoCmd is
> different. The Palm IIIx and Palm V devices have 68328EZ processor,
> not the 68328; the sound hardware changed in EZ. Thus, SndDoCmd is
> different.
>
> If you're whacking bits in the processor to make sound on the '328,
> your code will most likely NOT work on the EZ.
>
> If you're just calling SndPlaySystemSound, you should be ok.
>
> What does your software do?
It's a hack that makes the device completely silent. I could just
swallow up the sound calls, but then other hacks that trigger on them
would quit working. I wanted to avoid setting the volume argument to
zero, because the Snd... routines detect zero volume and just return
without doing anything. Setting volume to 1 has the desired effect on
my Palm III, but I've determined I need to set it to zero for my 5000
with Pro upgrade.
In the meantime, I've experimented and determined that I can just set
the volume to zero on my Palm III as well, with no adverse affects.
Will this also work on the devices that have 3.1 and the EZ processor?
--
Roger Chaplin
<[EMAIL PROTECTED]>
