[Coco] Coco 2 6847T1 test program

[Arthur Flexser]

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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> > Coco at maltedmedia.com
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> >
>
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