Date   : Sat, 01 Aug 2009 17:07:40 +0200
From   : rick@... (Rick Murray)
Subject: Fw: Fwd: ITV Teletext to shut down in January

Jonathan Graham Harston wrote:

> This is probably an egg-sucking masterclass here, but:

Not at all - I'm crap at maths so having all the numbers clearly laid 
out is a great help.

Thanks!


> Is that slow enough for:
>  
> .loop
> LDA &FCxx
> STA (zp),Y
> INY
> BNE loop
>  
> Porbably not. Probably need at least 42 bytes of buffer RAM and
> read it from there at your leisure.

Hence my suggestion to buffer the entirety of the VBI data (some 20ish 
lines) in RAM and refresh them when the rest of the (visual) frame is 
being 'drawn' to the receiver.

That said, I am seeing plenty of benefits into downloading data into a 
big RAM device for running 'freely' without so much subsequent computer 
intervention, if any...


Best wishes,

Rick.

-- 
Rick Murray, irregular internet access at local library.
BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...