[Coco] CoCo's TIMER and 60hz

Gene Heskett gheskett at shentel.net
Thu May 30 15:03:00 EDT 2019

On Thursday 30 May 2019 02:12:15 pm Dave Philipsen wrote:

> I think all *real* CoCos would nominally have the same VSYNC
> frequency. As far as finding a ‘test point’ on the system board to
> read the frequency, that would be fine but to be able to tune down to
> an accuracy of around +/- one second per day (which I think a good
> mechanical automatic wristwatches could achieve) you’d have to have a
> pretty accurate frequency counter that could differentiate between,
> say, 60 Hz and 60.0007 Hz.

And if the last msg was a bit garbled, the keyboard, but not the mouse 
failed while I was typing the reply.  The caps around the cpu have domed 
tops and may be in need of replacements.  About a dozen of them...

> Dave
> > On May 30, 2019, at 12:51 PM, Brock Harrison
> > <brock.erific at gmail.com> wrote:
> >
> > Might there perhaps exist a document illustrating the various
> > models' VSYNC frequencies, if they differ, and that which can also
> > provide some easily accessible locations on various motherboards so
> > as to validate current machine operation against these values?
> >
> > If so, the action of compiling a large list of empirical values from
> > users and plotting the deviation from nominal may suggest emulation
> > improvements and define soft real time clock module complexity
> > requirements.
> >
> > BH
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco

Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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