>
>
> The 1MHz video systems had a shift-register external to the
> CPU.  The XX MHz scenix chips and cute hacks for PICs are
> doing even the serialization in software...


Well, the specifications that I read from the OSI-CxP seemed to indicate
that they had an external character ROM and a video RAM. It would count
through the video RAM and look up the corresponding values in ROM and then
shift the data out to video. I'm not sure whether the 6502 did more than
just put the correct values in the video RAM, but I might of course also be
looking at the wrong schematics. The so-called "VDU" of the OSI-CxP seems to
have up to 15 chips associated with it in the schematics I saw. A similar
system could indeed be done using PICmicro, but I enjoy the one chip
solution I made myself, despite its limited abilities.

Greetings,
Maarten Hofman.
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