[Coco] RE: [Color Computer] Re: Lower case

[Mike Pepe]

The VDG with the integrated lowercase is known as the MC6847T1.

It also has an internal latch, so it saves on the external TTL chip to latch
the data into the VDG.

The last incarnation of the CoCo 2 shipped with this chip. In addition to
the lower-case character set, some of the uppercase letters are a little
different, I think the zero and letter O had some modifications, among other
things.

You can retrofit the 6847T1 into older CoCo's, you need to remove and bypass
the latch I believe in order for it to work properly. (no, I never did it
myself, but I recall seeing instructions in a popular CoCo magazine)

In the CoCo 1&2 days there were a few lowercase kits that contained an
external character generator ROM and some logic on a board. I recall them
being plugged into the VDG socket, and the VDG being relocated in a socket
on the lowercase board. 

Of course there was also the external word-pak(?) that was a separate video
display (6845 based) in a program-pak that could be used to display real 80
column text on an external monochrome monitor. Never had one either, I just
remember seeing them.

 
> I'd have to see it to believe it.
> Most "lowercase" add-ons for the CoCo just provided the ability to
> draw the letters on the hi-res screen.
> 
> 
> Now, the 6847 chip has the ability to access an external character
> generator ROM -- that's the default mode of operation on the NEC Trek
> computer.  I don't know if this was ever done with the CoCo.
> 
 



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