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From: jsgn3@tnofel.fel.tno.nl (Jos Groot)
Newsgroups: comp.sys.acorn
Subject: Can a Taxan MV795 monitor be used with a BBC B ?
Summary: Questions about connecting a Taxan MV795 monitor to a BBC B
Keywords: BBC B, Taxan MV795 multi-scanning monitor
Message-ID: <1991Jan25.075407.6481@tnofel.fel.tno.nl>
Date: 25 Jan 91 07:54:07 GMT
Organization: TNO Physics and Electronics Laboratory
Lines: 26


I recently bought a Taxan Multivision 795 (multi-scanning) monitor.
The specifications are very good, i.e., it can adjust itself to 
horizontal scan frequencies in the range of 30-57 kHz, and to vertical
scan frequencies between 50 and 100 Hz. However, this is too good
for my BBC model B (sniff !), that produces a vertical sync pulse
with a frequency of 15.625 kHz. Now the video signal of the BBC is 
controlled by two IC's, the 6845 CRTC and the video ULA. I think
it should be possible to alter the (timing) registers of these two
IC's in such a way that the Taxan can be used with the BBC B. I
tried this yesterday, and it looked promising (and, as a bonus,
demonstrated that the Taxan can produce some musical whistles). My
experience with the CRTC and ULA is too limited to figure it out
in detail. So my questions are:

1. is it possible to use the Taxan with my BBC B, in all 8 screen modes ?

2. what are the values I have to put in the various registers of the
   CRTC and ULA to produce an image, for all screen modes ?

Thanks in advance.
-- 
Jos Groot
Physics and Electronics Laboratory FEL-TNO
P.O.box 96864
2509 JG  the Hague