[BBC-Micro] Ground Control UTA-1 Teletext Receiver: The Gory Details

Philip Pemberton philpem at philpem.me.uk
Wed Feb 10 19:12:20 GMT 2010

Rick Murray wrote:
> On 10/02/2010 02:11, Philip Pemberton wrote:
>> Note that this is the first time (that I know of) that the UTA-1's
>> secrets have been publicly disclosed...
> If I can find mine, I can take a bunch of photos! :-)

That would be nice.
(This from the guy who has a digital camera and the UTA on the desk next 
to each other... laziness much? :) )

> The later tuner... It is marked U944C/IEC which I believe is a Sony 
> part?

Sounds more like a Philips part number to me. The tuner in the UTA-1 is 
a Mullard U912 or something like that. Can't be bothered popping the 
cover for a fourth time to find out, though.

> On the other hand, it is entirely possible this is a UHF-only tuner, so 
> the lack of band selection is irrelevant.

The tuner in the UTA-1 seems to be single-band UHF-only. None of the 
port pins on the CITAC (P10-P13 and P20-P23) are even soldered down, 
much less connected to anything.

> I used a slightly more devious method than you, but one that worked just 
> as well.
> I used Zap to extract the IIC module.
> I changed the SWI call to be IIX_Control, with the module being IIX.
> I cobbled together a module called IIC with the command IIC_Control. 
> This would log the status on entry, call IIX_Control, then log the 
> status on exit.
> I then ran my !Teletext software with Colin's module, and observed what 
> it was doing.

Colin who?

> When reading the WinTTX source code (to be released RSN), keep in mind 
> that IIC addresses are the UPPER seven bits, with the LSB indicating 
> read or write...

I don't have to worry about that -- my I2C driver does it for me :)
If you initiate a write it will clear the R/W bit; if you initiate a 
read it'll set it.

> At any rate, it is easier than making sense of the stuff in the UV1316 
> datasheet. :-)

True. But the FI1216Mk2 and FI1236Mk2 are nice and easy to understand. 
"Multiply this by that, then add this, then send it to the chip."

> If you're interested in various datasheets for the original cheese-wedge 
> receiver (I'd *LOVE* to know how that works), then please visit the 
> unlinked page:
>   http://www.heyrick.co.uk/software/winttx/datasheets.html

Hey, great -- a scan of the Philips EURO-CCT User Manual. Nice!

I've got my UTA hooked up to the PC at the moment (via a ByVac BV4221 
USB-to-I2C bridge board). It seems to be tuning, but I need to hook up a 
monitor or speaker to the AUX socket to be sure. Hmm... phono cable and 
some hookup wire?

philpem at philpem.me.uk

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