[Coco] CoCo 1 & 2 Compatibility Question...

[Barry Nelson]

Actually, later versions of the CoCo 2 had true lower case. If I remember correctly, these machines also lacked some of the semi-graphics modes, but I am not sure.

Very late in the CoCo 2 production run, an enhanced VDG was available. Called the 6847T1, it included a lower case character generator and the ability to display a green/orange or black border on the text screen. Its other changes were mainly to reduce parts count by incorporating an internal data latch. The lower case capability of this VDG is not enabled by default on this system and is not even mentioned in the manual. Only through some tinkering and research was this feature discovered by intrepid CoCo users.
The 6847T1 may also carry the part number XC80652P; these may have been pre-release parts. 

On Jun 8, 2015, at 9:27 PM, coco-request at maltedmedia.com wrote:

> Date: Mon, 8 Jun 2015 21:07:39 -0400
> From: Arthur Flexser <flexser at fiu.edu>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Subject: Re: [Coco] CoCo 1 & 2 Compatibility Question...
> Message-ID:
> 	<CA+LuDcfoaPtsRVNEZF2ZfjTnM0u=2pif=DVt68v3rSxkXQeXEA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
> 
> Huh?  The CoCo 2 was virtually perfectly compatible with the CoCo 1.  It is
> the CoCo 3 that sometimes presents compatibility problems with the CoCo 1
> and CoCo 2, though even there, the huge majority of software that runs on
> the earlier CoCos will also run on the CoCo 3.  (Or did you mean
> INcompatibility?)
> 
> Art