[Coco] Coco 2 6847T1 test program

Ciaran Anscomb cocomalt at 6809.org.uk
Thu Jul 20 03:23:56 EDT 2017


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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