[Coco] Coco1 FPGA

[Mark McDougall]

Well, all this talk has prompted me to port my WIP Coco1 design to my latest
hardware platform. Here are the results of tonight's efforts...

<http://members.iinet.net.au/~msmcdoug/pace/platforms/pace-p2/coco1_cvbs.jpg>

On the left of the picture is my hardware platform.
On the right is the (currently rather crappy) output on a composite monitor
- 60Hz PAL atm. As you can see, the video needs tweaking as the left-most
column is repeated and the right-most missing. One difference with the newer
version is that orange is now actually orange, thanks to 12-bit colour
resolution.

I briefly had it running VGA output tonight - same video quirks but of
course flawlessly crisp picture.

For those interested, the design emulates the Coco 1, with the 6883/6847
implemented only to the point of being able to display the standard text
screen. This requires 3,921 LEs, or 12% of the EP2C35. Of those, 3,064
comprise John Kent's CPU09. As you can see, I'm not going to have much
trouble fitting the whole design into the device - and then some.

Now where did I put those 6847 datasheets... ;)

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"