Re: Multistandard composite to RGB board

From: Hársfalvi Levente (
Date: 2008-05-21 22:09:07


Well... indeed...

...Honestly, this one started off as something "simple" (find plans, 
order PCB, buy components, put things together and move on... you get 
the idea). But it just didn't work well... it needed fixing, some 
enhancement, and at the end it got slightly more complicated than ever 
expected, as much as I was just happy that it did work well (after 
all)... Then I faced the fact that I didn't have more time and attention 
to spend on the thingie, thus the compromise (no more work on the 
design, but providing a fairly complete doc... from that on, the 
possibility is there).

For a production model, one would have to do a cleanup (do a less 
complicated clock part, reduce the number of switches, invent a new way 
of providing proper black level, finally, design a new PCB that fits in 
some available housing)... In fact I've been thinking on a possibility 
to mis-use an AtTiny25 as a PLL-alike clock synthesizer (I'm still not 
sure that it's possible, but my nose tells me that it likely is). 
Another small microcontroller could deal with sync and black level (thus 
omitting both the LM1881 and the 74ls04)... this would make the design 
more complicated, but would also make the final product smaller and 
cheaper to manufacture (let alone the fact that it won't depend on the 
availability of some esoteric values of crystal frequencies anymore... 
:-) ).

MagerValp írta:
>>>>>> "HL" == Hársfalvi Levente <> writes:
> HL> Some months ago, I might have asked here whether someone knew of a
> HL> simple unit decoding more esoteric composite video signals (PAL-N
> HL> in particular) to standard RGB. I couldn't find a suitable design
> HL> back then (I could find things, however, that set me on track), so
> HL> I built one myself. Currently, it decodes PAL, NTSC, PAL-M, PAL-N
> HL> and SECAM from composite and S-Video to analog RGB (suitable for
> HL> displays with SCART socket, for example).
> That's a really nice design - I only wish someone would produce and
> sell them at a decent price.

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