Date   : Fri, 22 Dec 2006 09:03:12 +0000 (GMT)
From   : info@... (Sprow)
Subject: teletext - was: Curse of the long TUBE cable

In article <00a801c72499$598fa1d0$3201a8c0@...>,
   David Hunt <dm.hunt@...> wrote:
> > >Sounds like a nice hairy project for someone! A box that modulates a 
> > >Teletext signal from a embedded PIC/FPGA/CPU board etc.
> > >
> > >I'd pay ?50 for one of these.
>
> > A google for "teletext generator" brought this up on #1 slot:
> > http://www.fab-online.com/eng/teletext/basic/dg.htm
> > "FAB Teletext Data Generator is used for transmission of 
> > teletext and teletext subtitles.
>
> I found this http://lea.hamradio.si/~s51kq/TTX.HTM which looks interesting.
> The only problem is the board and software aren't ready, that was dated
> August 2004. 
>
> A complete unit sells for over 1200 Euro.

I'd be sniffing round chip vendors instead. For example Analog Devices
ADV7171 does everything you need: PAL/NTSC output, ability to turn on
teletext insertion on a line by line granularity, simple I2C register
interface, built in test pattern generator (since you need the rest of the
picture too!).

This particular device is sub $10, and there's a handy eval board for $300.
The one extra bit of work which would be required would be taking the TTXREQ
(clock out) line and using it to strobe serial data on the TTX (data in)
line so that the teletext data could be stored as bytes in SRAM.

Fun for someone,
Sprow.