Date : Wed, 26 Feb 2003 17:40:41 -0000
From : "Richard Gellman" <splodge@...>
Subject: Re: Master 128 on a TFT flat screen???
> Also, I believe a VGA signal uses separate horizontal and vertical sync
> lines, whereas the BBC's sync output is composite, so you'd need to
> arrange a sync-splitter.
There is a chip, still widely available (maplins has them) called LM1881.
Its a sync separator chip, 8 pins, and allows you to separate line sync and
from a composite sync signal, and alows has a couple of other outputs, such
as "odd/even field".
>It's a shame,because the syncs are available inside the BBC seperate - you
>just never see them on the external connectors.
Well, if your creative enough with a soldering iron... ;)
>> If there's an online archive of Mike Cook's Body Build articles anywhere,
>> I believe he covered BBC->VGA converters back in the days of The Micro
Such articles are when I learned of the LM1881 - specifically an article on
constructing a frame-spanned video digitiser.
>I'd have thought the biggest hurdle these days is finding a monitor which
>will scan as low as 50Hz/15.625kHz field and line rates,
Technically, VGA/SVGA monitors are supposed to be able to deal with such low
screen rates by default, as the old EGA text modes (that the PC BIOS uses on
startup) are rather low scan rates. However you may find newer monitors dont
bother and presume the card will "emulate" the EGA, that is, generate EGA
output, but at a higher scan rate.