I wrote:

> I seem to recall that using 50% duty cycle PWM on a PIC using a 19.6608
MHz
> crystal, further divided externally with N number of flip-flops gave me
> tones in the equal tempered musical scale including 440 Hz -- I'll see if
I
> can dig up the details.


Hi Koen,

Well, I dug up the details. Sorry, using PIC PWM module and 19.6608 MHz
crystal produced only approximations to the musical scale -- would have
drove people with perfect pitch crazy.


The two closest frequencies to 440 Hz were:
        441.38
        438.86


I still thing the CD with pre-burned 440 Hz wave files would make a good
cheap tuner.

You could even use a portable CD player to play the tones.

Best regards,

Ken Pergola

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