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From: glen herrmannsfeldt <g...@ugcs.caltech.edu>
Newsgroups: comp.os.cpm
Subject: Re: semi-ot: motorola 6847
Date: Sun, 3 Jun 2012 16:25:41 +0000 (UTC)
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Roger Ivie <ri...@ridgenet.net> wrote:
> On 2012-06-03, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
>> The 6847 was the basis for the TRS-80 color computer.

> The color computer and similar Dragon machines were pretty much
> right out of a Motorola app note for the 6883. I used to have
> a copy of the app note; not sure how easy it is to find these days.

> http://en.wikipedia.org/wiki/Dragon_32/64

I think I still have the CC service manual. I will have to
dig it out.

>> That, and the 6883 along with the 6809 were pretty much used
>> as designed by Motorola. I believe the 6847 works without the
>> 6883, but I am not completely sure about that.

> IIRC, the 6847 is close enough to pin-compatible with the 6845
> that people used it as a drop-in replacement.

When I first got my CC, I ordered the data sheets for the chips,
plus the 6845. I didn't remember them as being that close, but maybe.

The 6845 is more general purpose, though. All the timing is 
programmable, where the 6847 has specific video modes.

-- glen