Re: [uCsimm] Simple PWM audio driver

From: Pascal Bauermeister (pascal.bauermeister@smartdata.ch)
Date: Mon May 07 2001 - 16:44:12 EDT


David Beckemeyer wrote:
>
> > I suppose you have a filter at the output of the pwm (i.e. driving a
> > real speaker, not a buzzer).
>
> Right, you need appropriate hardware for generating line-level
> or amplified output. Anything from a cap and variable resistor
> to a more sophisticated filter/amplifier arrangement. There is
> an APPNOTE from Motorola, but I think it has a typo:
>
> http://e-www.motorola.com/brdata/PDFDB/MICROPROCESSORS/32_BIT/68K-COLDFIRE/M683XX/MC68EZ328PWM.pdf
>
> There are probably other circuit designs floating around too.
>

Thank you David.

I asked this because we are using the PWM directly connected to a buzzer in order to do simple beeps, not play sampled sounds. So we have directly connected the buzzer to the PWM output. We'll never achieve audio quality with this (it's not our aim), and moreover, playing sampled sound in ubyte raw format will probably _not_ give even bad results.

Regards,

  Pascal
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