🚀 go-pugleaf

Well, I have hunted back thorough the last 70 messages of comp.sys.acorn.tech
and only found one messages entitled 'Re: Hi res modes' - I suppose I shall 
have to go and find an archive of it - or would some kind person like to
email me a copy of the thread ?

I have a PCATS graphics enhancer card (yes, they *do* work on A5000's - I
don't know why Serial Port/Vertical Twist/etc/etc say they don't), and that
is easily the best way to play with VIDC speeds. I have a 40MHz and 48MHz
clock crystals, and you can easily switch between them in software. That 
way you can have your 800x600 mode on the 36MHz crystal, but switch to the
higher rates for better resolution, or whatever.

The factors that govern VIDC performance at high speed are unclear, and there
is a lot of variation from VIDC to VIDC. For instance; Brian Brunswick can
happily run 800x600x256 col on an old A440, but me with a relatively new
A5000 + 12MHz memory system cannot (the memory would have made the mode usable,
but the VIDC can't quite hack it 8-( I can manage stupidly high refresh rates,
and high resolutions using the 48MHz crystal though - as long as they are 16col
modes.

Nick.
--
Nick Smith, Churchill College, Cambridge, UK.  %$%  Email: nas20@uk.ac.cam.phx
sig quote wanted - must be under guarantee.   $%$  --- Usual disclaimer. ---