Date   : Fri, 05 Aug 2011 02:30:24 +0200
From   : rick@... (Rick Murray)
Subject: Morley teletext adapter anyone?

On 05/08/2011 00:23, stuart wrote:

> I think that would be a shame, even more so since there appears to be
> no information about the hardware used in the adaptor on the web.

I'd imagine the Morley box is quite similar to the Ground Control unit, 
which is detailed on my site ( .../software/ttx/ then some link like 
"how it works" ).

Perhaps the only sticking point is if it uses CITAC tuning (a chip 
generates tuning voltages) instead of the tin-can tuner doing it by 
itself. Basic operation is the same, but different methods using 
different IIC addresses. I guess it depends upon the vintage of this 
decoder (the original UTA-1 Ground Control had a CITAC, the UTA-3 had a 
tin-tuner (and because of this, not compatible); never seen inside a UTA-2).

As it is a user port connection, it'll almost definitely be bit-bashed 
IIC, which means we're looking at the SAA524x (I don't think the gen 1 
decoders did IIC without a little MCU?). It would be interesting to see 
how much SRAM they gave it.

Much of this is, of course, conjecture at this point. ;-)


Best wishes,

Rick

(originally sent from my mobile...to Stuart... grrr the Reply-To fail)

-- 
Rick Murray, eeePC901 & ADSL WiFI'd into it, all ETLAs!
BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...