[Coco] 6847 external character generator

Zippster zippster278 at gmail.com
Sat Feb 28 21:47:31 EST 2015


Hi Joe,

Yes, that’s me.  I built one, it works great.  Kind of a big prototype
with the standard 74 series logic chips though.

You can see it here…

<https://sites.google.com/site/thezippsterzone/home/coco2-projects/mc6847-external-character-rom <https://sites.google.com/site/thezippsterzone/home/coco2-projects/mc6847-external-character-rom>>

I recently got back prototype boards using CPLDs for the logic that
makes for a convenient board size. 

Pics here... 

<https://drive.google.com/folderview?id=0B1sgl615FlGnd1VlcWtJQmhNYm8&usp=sharing <https://drive.google.com/folderview?id=0B1sgl615FlGnd1VlcWtJQmhNYm8&usp=sharing>>

I may move the logic into a single surface mount CPLD and shrink it a bit, but I was also thinking
with the PLCC sockets these could be assembled as kits pretty easily.

I also put together an excel file that makes it easy to design the fonts in a graphical manner.
It generates the hex code which you can then copy and paste into a Hex editor to make the bin file
for your ROM.

- Ed



> On Feb 28, 2015, at 8:00 PM, Joe Grubbs wrote:
> 
> I think Ed or perhaps someone else was making significant strides on an external character generator for the 6847. Did this ever become a thing? I might be interested in one if so.
> 



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