[Coco] MC6847 External Character ROM

[Luis Antoniosi (CoCoDemus)]

I have a pink 6847. It probably blew the R-B output.

Luis Felipe Antoniosi



On Mon, Jan 19, 2015 at 2:52 PM, John W. Linville <linville at tuxdriver.com>
wrote:

> On Sat, Jan 17, 2015 at 03:39:43PM +1000, Nick Marentes wrote:
> > On 17/01/2015 12:15 PM, Luis Antoniosi (CoCoDemus) wrote:
> > >I a nice improvement would be using SRAM and allowing the coco to
> change it
> > >on the fly using some port. The SRAM would be dumped from ROM upon
> reset.
> > >
> > >Just in case you end up without any other project ;)
> > >
> > >
> > >
> >
> > You took the words right out of my mouth Luis!
> >
> > Why just a ROM with a fixed character set when you could add some SRAM
> and
> > give the CoCo1/2 the ability for a programmable character set (or PCG
> > graphics).
> >
> > It would be possible to create 256x192 graphics on a screen that only
> > occupies 512 bytes!  And it would be fast.
> >
> > Several computers of the time had this and I was always dissapointed that
> > the 6847 VDG wasn't designed with this capability.
>
> You'll be limited to one of two 2-color options with these "graphics",
> of course.  It could still be interesting, but it looses some luster
> when you have to choose between light green & dark green or light
> orange and dark orange... ;-)
>
> John
> --
> John W. Linville                Someday the world will need a hero, and you
> linville at tuxdriver.com                  might be all we have.  Be ready.
>
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