[Coco] Re: [Color Computer] CoCo 2 questions.

[Mike Pepe]

Phill Harvey-Smith wrote:

> Wouldn't mind a copy of that, do you have somewhere where you could put
> it temporarly for until I can download ?

Sure, grab it here:

http://www.doki-doki.net/~lamune/temp/coco2b.tif

> Right, I did wonder what those white connectors where for, daughtercard
> with 8x41256 presumably :)

Exactly correct. Not much different than the CoCo 3 512k upgrade actually.

> Nope was not that.
> 
> 
> 6809 is alive and kicking, turned out to be the 4416 RAM chips, replaced 
> them with a couple of 4464s scaved off an old MDA card, set the 64k link
> and presto it fired up.

Aha, excellent.

> What's the difference between the normal 6847 and the T1 ?

A few significant differences. One difference is that you can select 
green or black border in text mode. Another is the ability to display 
real lowercase in text mode as well. Architecturally it's different in 
(from what I've been able to discern, since I have no real datasheet on 
it) is that none of the upper address lines (A1 and up) are physically 
connected. Also there's an internal data latch, which eliminates the 
external 8 bit TTL latch all other CoCos have for VDG data. I think that 
because of this, the T1 is probably incapable of functioning in a system 
without the SAM to drive it. Again without the datasheet I can't be 100% 
sure of that.

The real lowercase is what probably was of interest to most people. Also 
note that despite this enhancement, Tandy never exploited it, advertised 
it, or even mentioned it. It was just the fact that someone noticed that 
the 0 and * characters on "these new CoCos" looked weird!

> Right, that makes sense....though this A now has 64K :)

Feel free to label it 26-3127B now...

heh


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