[Coco] [Color Computer] WordPak RS/CO80

[Boisy Pitre]

I've made some progress... apparently the Rockwell 6545 is very similar 
to the Motorola 6845, and there is a great deal more information on the 
net about this chip.

I found the info at 
http://members.tripod.com/~oldboard/assembly/6845.html to be helpful.  
It details a set of values to plug into the 6545 in order for it to 
display properly.  Using the values from the CO80 column, I've managed 
to make the display look coherent.  No more wavy out of sync lines.  I 
get a nice 80x25 display with a bunch of junk characters.  However, I 
have no idea how to change the contents of the screen (i.e. the 
characters).

There is a 6116 (2Kx8) RAM chip onboard which connects to the 6545, as 
well as a 2K Character ROM.

It appears that $FF78 and $FF79 are mirrored at $FF76 and $FF77.  So 
now all that needs to be done is to solve the mystery of how to write 
characters to the internal RAM so that they are displayed on the 
screen.

On Jan 3, 2005, at 5:50 PM, Bob Devries wrote:

> Boisy, I seem to remember that there was something different about the 
> WordPak-RS compared to the other PBJ 80-column cards. I wrote a BASIC 
> driver for this card way back, and maybe a OS9 one too, and I do 
> remember that some values written to the 6545 registers needed to be 
> different.
>
> I'll see whether I still have information on this, or whether the 
> driver I did is still in existence.
>
> --
> Regards, Bob Devries. Dalby, Queensland, Australia.
> Faith isn't faith until it's all you're holding on to.
> http://e4god.com/freeblogs/bdevries/
>
>
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