[Coco] "VideoPak" hardware question

nickma2 at optusnet.com.au nickma2 at optusnet.com.au
Sun Nov 9 20:30:22 EST 2014


Now here's an idea for Luis!...

He has his scandoubler working to display the CoCo's 15Khz output onto
a 31Khz VGA screen.

This doesn't make the CoCo into VGA resolution, just doubles the
scanlines by running each one twice (non-scanline mode).

What about having the CoCo display two 320/640 x 225 images,
alternating between the 2 and Luis's circuit display the first image
as:

CoCo video data scanline then blank scanline (as the scanlines mode
does currently)

then on the next frame which will have switched, be displayed as:

blank scanline, CoCo video data scanline.

The idea would be to display each CoCo page in succession but they be
offset by 1 scanline.

There will be slight flicker but the end result would be a 320/640 x
450 "VGA" display.

Of course, this only useful for the display of images and it doesn't
add any extra colors as such.

Pretty useless unless it can be had without incurring any extra cost.
More a fun feature than anything practical.

Nick

----- Original Message -----
From: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
To:"CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Cc:
Sent:Sun, 9 Nov 2014 19:08:53 -0600
Subject:Re: [Coco] "VideoPak" hardware question

 Sure, you could interface a VGA chip of some kind to the coco,
 but as others were saying, what about software.
 If a graphics solution doesn’t support the original software,
 probably not a good solution.

 Seems to me that the best way of “modernizing” graphics for
 the Color Computers is probably FPGA emulation of the GIME
 and/or 6847 chips.

 That way you could interface to a variety of video output options,
 run all the old software, and add new capabilities (sprites, etc)
that
 newly written software could take advantage of.

 - Ed

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