Re: CBM 900 info posted

From: Richard Atkinson (
Date: 2000-09-06 14:22:46

On Wed, 6 Sep 2000, Nicolas Welte wrote:

> Many thanks for the great pictures and the chip list, Bo! The LR video
> board obviously uses a normal Hitachi 68B45 video chip, so my guess is
> that the 8563 was used on the HR (high-resolution) board of the
> workstation machine. Do you know someone who owns a 900 workstation?
> Maybe the guy who sold you this 900 server? I'd really like to know
> about the HR video board :-)

I'll second that, Bo - damn nice pictures! Change the "video chip" section
in your tech specs to read 6845.

I'm going to put the case that the HR video board doesn't exist and in
fact never existed. When Bil Herd was put onto the C128 project, he was
offered the 8563 from the then-abandoned Z machine project, which was
still in a very early stage of development and didn't work much at all.
The chip had appalling yield rates and I doubt very much there are any
production-style HR boards. There may be a *handful* of development
prototypes, but these will have the flakiest 8563s you've ever seen and
are *extremely* unlike to work at all now. Fortunately, if you ever did
come across such a board, you could always substitute the 8563 from a
"modern-day" C128. I think Commodore kept the bus timing the same, which
explains the awful software interface with the VDC on the C128.


Richard Atkinson
Software Engineer
Tenison Technology EDA Ltd

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