Re: Multistandard composite to RGB board

From: matt (
Date: 2008-05-22 12:52:52

do you have to generate the sandcastle pulse??
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----- Original Message ----- 
From: "Hársfalvi Levente" <>
To: <>
Sent: Thursday, May 22, 2008 8:09 AM
Subject: Re: Multistandard composite to RGB board

> Hi!
> 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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