[Coco] MC6847 ( Motorola DS9823)

[Arthur Flexser]

Interesting that Bob Rosen said Spectrum Projects was working on an
adapter board to allow earlier CoCos to use the 6847T1.  Don't recall
such a board ever being advertised by them, so it's likely the project
never made it to market.  Would such a project have involved anything
more than rerouting a few lines to connect to different pins, similar
to the adapter to allow a 28-pin EPROM to be used in a disk controller
with a 24-pin ROM socket?  Seems like there'd have been some demand
for such an adapter.  A simpler version of Green Mountain Micro's
Lowerkit (tip of the hat to Dennis Kitsz), which I had in my CoCo 1.

Art

On Thu, Mar 21, 2013 at 10:53 PM, Stephen H. Fischer
<SFischer1 at mindspring.com> wrote:
>
> ----- Original Message ----- From: "Bill Pierce" <ooogalapasooo at aol.com>
> To: <coco at maltedmedia.com>
> Sent: Thursday, March 21, 2013 7:24 PM
>
> Subject: Re: [Coco] MC6847 ( Motorola DS9823)
>
>
>>
>> Since the real search is for the datasheet for the MC6847T1,
>
>
> Hi,
>
> My printed CoCo 2 Service Manual does NOT have the appendix.
>
> I now have confirmed that I did not find a CoCo 2 Service Manual earlier in
> the day.
>
> I think that we did this same exercise a few years (Decades) ago.
>
> I did find this in the July 1985 Rainbow:
>
> ---------------------------
> . . . BUT WORKING ON IT
>
> Editor;
>
> Referring to Gary McConville's letter on
> Page 8 in the May 1985 rainbow that claims
> the new Motorola VDG chip (the 6847-T1)
> is "pin for pin" compatible with the old 6847,
> this contradicts the data my company has
> received from Motorola. The information
> about the 6847-T1 clearly shows it has a
> different pin configuration.
>
> Spectrum Projects is currently investigat-
> ing a satellite adapter board to retrofit older
> CoCos with the new VDG chip. The main
> advantage of this new chip is true lowercase
> letters instead of reverse video. Also, the
> new 26-3 134B and 26-3 136B CoCo 2s will
> fully support the double speed poke.
>
> Bob Rosen
>
> President, Spectrum Projects
>
> Woodhaven, NY
>
> ---------------------------
>
> No joy either with the alternate part number.
>
> SHF
>
>
>
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