Re: 8032 music

From: Rhialto (
Date: 2005-01-03 02:09:14

On Mon 27 Dec 2004 at 14:06:39 -0700, Rich wrote:
> I recently acquired an 8032 and I'm looking for some code to drive the
> peizo speaker with the VIA chip.  Does anyone have a good starting
> point?  From what I've been able to determine you use the shift
> register functionality on the VIA to drive the piezo speaker.  I'm
> guessing that you'd have a periodic interrupt routine to change the
> shift register data/control in order to play the melody.  Am I on the
> right track?

The common idiom is to

    1. enable the shift register - poke 59467,16
    2. set the desired wave form in the shift register - poke 59466,15
    3. set the desired frequency (actually time between bit shifts) -
	poke 59464,whatever

If you want to play some melody, you repeat step 3 periodically.

Be sure to undo step 1 before using the tape recorder - poke 59467,0.
I used to know these numbers off the top of my head, but I had to look
them up this time.

> Thanks!
                           -- Ceterum censeo "authored[1]" delendum esse.
___ Olaf 'Rhialto' Seibert -- [1] Ugly English neologism[2].
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