Re: Apple II Speaker

["Bill Garber" <willy46pa@comcast.net>]

"M. Pender" <mpender@hotmail.com> wrote in message
news:7yQxb.6294$a54.5406@nwrddc03.gnilink.net...
> Bill Garber <willy46pa@comcast.net> wrote in message
> oJWdnTSVzej4mlqiRVn-tA@comcast.com">news:oJWdnTSVzej4mlqiRVn-tA@comcast.com...
> >
> > Is there a place I can read the numeric
> > values of the signals being sent to the
> > A2 speaker? I know that it is being fed
> > pulses at different speeds to create the
> > pitch, but I need to be able to distinguish
> > one tone from another for a program I want
> > to write. If I find this info before I get
> > replies I will post as such.
>
> IIRC the A2 speaker is connected to a toggle that is flipped by either
> reading or writing to a softswitch ($c030?), so any attempt to read that
> memory location would result in additional toggling of the switch.  Again,
> IIRC a write to the switch toggles it once and a read to the switch does a
> double-toggle.
>
> One approach would be to attach a diode and RC circuit to the speaker
output
> and determine the frequency indirectly.  The voltage across the capacitor
> would vary according to the toggle rate of the speaker.
>
> That said, I think tones are generated using a system function and the
tone
> parameters could be read without directly affecting the speaker.  I expect
a
> similar system function also exists for the IIgs ensoniq chip.
>
> Can you tell us a little more about the project?

Sure. What I hope to accomplish is to separate
the sound signal into high and low. I found a
circuit that will do this. I also think that
instead of that, being that the highs and lows
would be unequal, that a simple flip-flop of the
signal, first to speaker 1 and then to speaker 2,
would give me closer to the real result I am
looking for. I have some 556 timers and a bunch
of LM324 quad Op-Amps that I will play with to
see if I can get it to play for a few mS thru
speaker 1 and then a few mS thru speaker 2.
Should prove very interesting at the very least.
Stereo? No. Improved game sounds? Maybe. Just for
fun is all. For now. I'm tackling a new Apple II
frontier. Slotless interfacing. It is showing me
quite a bit about how the Apple II works internally
and getting past the hurdles that slots take care
of for you is intriguing. My goal is to eventually
be able to interface devices to the IIc family.
This is no easy task, as many of the devices that
are already interfaced do not work exactly the
same as the slotted IIs, although they are nearly
100% compatible. I say nearly only because I've
heard that some programs don't run properly even
though they do run. I hope to have a couple things
working by next KFest, giving me more reason to
attend. I just hate coming out with nothing to show
everyone. ;-) Anyway, This speaker thing is one of
the simpler things I'm messing with, no biggie.
Just something to play around with when I get tired
of working on the real stuff. Thanks for any help
you can offer. BTW, glad to hear that you got the
network up and running.

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - willy4SPAM6pa@comXcast.net
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