Coco2: mystery IC

[Steve Adolph]

Hello-

I have a 64k Coco2 with PCB number 20261058 that has a chip on it that I
cannot identify--

it is a 40 pin DIP

it is labelled XC80652P
It is Motorola.

Can anyone help with what this chip is?

Thanks, Steve

[Michael Black]

It was easier to dig out a CoCo than it was to dig out a manual.

It's the VDG. That's easy by accounting for the large ICs on the board.
And in my case, I added a wire to get proper lowercase, so that's
a backup bit of information.

It was a 6847 in the earlier CoCos, and it's still a 6847 in these
CoCos. But, it's a later variant (the magazines tacked on some suffix if
I remember rather than listing it as a different part number), and
has hardware lowercase rather than the uppercase on a reversed field
that we had to suffer through in the earlier days of the CoCo. I actually
got this one long after I got a CoCo III, so the lowercase never did me
much good.

I can't remember the details, of what the jumper was for, well it must
be for getting the lowercase, or if the lowercase can be turned on through
software. It was well written about at the time, so all you have to do
is look through the old magazines. Likely one can find some infor
doing a websearch.

Michael

[sadolph]

Michael,
thanks for confirming that. I was suspecting it was the VDG. It seems that
there are a few chips made specifically for Coco, like the part that
integrates the resistor network used to make a DAC for sound..that was
discretes, but got integrated into a chip for mass production, or so it
seems.

Anyhow I was wondering about 'reverse video' hack on the old cocos. I
remember doing it when I was a kid, but now I cant find a reference for
that.

thanks, Steve

"Michael Black" <et...@FreeNet.Carleton.CA> wrote in message
news:c2im4t$5l6$1...@freenet9.carleton.ca...