Date   : Wed, 29 Nov 2006 12:28:41 +0000
From   : pete@... (Pete Turnbull)
Subject: Running on an NTSC display?

On 29/11/2006 10:05, Peter Coghlan wrote:
>> For all, you'll need a different MOS so the 6845 CRTC gets poked to generate
>> 60 fields a second and appropriately reduced line count.
>>
>> For composite, the colour crystal needs changing from 4*4.43 to 4*3.59.

> Theres got to be a bit more to it than that. Theres more to the differences
> between NTSC and PAL than just the subcarrier frequency. I suspect that
> a board modification of some sort is required to undo the extra feature(s)
> PAL has over NTSC.

Nope.  All you need do is change the crystal and reprogram the CRTC -- 
which is done by changing the MOS.  If you only want B&W you don't need 
to change the crystal, and if your monitor can handle European 
line/frame rates you don't even need to change the CRTC parameters.

-- 

Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York