[Coco] Coco 2 6847T1 test program

Ron Klein ron at kdomain.org
Thu Jul 20 15:12:06 EDT 2017


Hi Art,

I heard about that, too, from Simon.  Great tip and that it an easy way to
tell!

Thanks

-Ron


On Thu, Jul 20, 2017 at 2:00 PM, Arthur Flexser <flexser at fiu.edu> wrote:

> You can't detect the T1 VDG from software, but that doesn't mean you have
> to crack the case open to tell.  Even without invoking the true lowercase
> mode, there are differences in the fonts.  If I'm recalling correctly, the
> T1 font has a slashed zero, for example.
>
> Art
>
> On Thu, Jul 20, 2017 at 2:54 PM, Ron Klein <ron at kdomain.org> wrote:
>
> > Hi Ciaran,
> >
> > I appreciate the information, sir.
> >
> > My curiosity about this stemmed from an issue that was discovered with
> the
> > MC-10 driver under MAME which continued to the Coco 1 and Coco 2 drivers.
> > I was helping one of the MAME developers with some testing (on real
> > hardware) and wanted to be sure my Coco 2 was not a "B" / T1 version.
> One
> > can always crack the case open, but I was looking for something that
> could
> > provide a visual verification through software.
> >
> > Thanks!
> >
> > -Ron
> >
> >
> >
> > On Thu, Jul 20, 2017 at 2:23 AM, Ciaran Anscomb <cocomalt at 6809.org.uk>
> > wrote:
> >
> > > Ron Klein wrote:
> > > > Somewhat related so for those who use MAME, there was a SG6 issue
> that
> > is
> > > > now being addressed by one of the MAME developers.
> > >
> > > Is this where the value on the data bus is interpreted as font data?
> > > With bit 6 inverting as usual, so bit 6 colour ends up fixed.
> > >
> > > Used to good effect in the Dragon User published BASIC + M/C game Flee!
> > > (exclamation mark in title).
> > >
> > > Dragon 32 (original) and Dragon 64 ([m]) versions (not CoCo compatible)
> > > here:
> > >
> > > http://www.6809.org.uk/tmp/da/dragon_originals/
> > >
> > > To the original question: if it was to determine T1 presence
> > > programatically, I don't think you can.  The VDG doesn't provide
> anything
> > > you can explicitly read; there'd have to exist some slightly different
> > > side-effect (e.g., hsync timing) for it to even be possible, and I
> really
> > > doubt there are any.
> > >
> > > ..ciaran
> > >
> > > --
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> > >
> >
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> >
>
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