RE: PC speaker

From: Maciej W. Rozycki
Date: Wed Jun 13 2007 - 06:27:19 EST

On Tue, 12 Jun 2007, Jan Engelhardt wrote:

> >4) It assumes the current will be sufficient to burn out the speaker. (I
> >know it will get very hot on older machines, whether it will burn out --
> >might even depend on the exact speaker model.)
> Since you can set the x86's crystals frequency from 1193182 to 18 Hz
> (PIT_TICK_RATE / 1 to PIT_TICK_RATE / 65535) [*], you can never really
> bust it. But even then, what would a speaker do it was constanly given

I am fairly sure you have a choice between a steady low and a steady high
level on the speaker output available if you switch the 8254 to the right
single-shot mode. In case you have not been into such details -- the 8254
offers six modes of operation, selected for each channel separately, of
which only two are periodic.

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