19/03/2004 08:54:44, Paul Carpenter
<
paul@pcserv.demon.co.uk> wrote:
>I noticed the site from the recent Electronics Weekly write up on
Aleph and
>the Balloon board...
Woo! Fame!
>Looked around the site and see some interesting things, noted
that someone
>was interested in video grabber boards, one of my fortes...
Ah, that'll be me, then... Not least because I seem to have 300-
odd Sony CCD & lens blocks cluttering my house.
http://pub.se7ens.net/lists/cam7/EVI-101_side_on_a.jpg
They're PAL output, and when they work, they're rather spiffy.
Nice optics, decent CCD. When they don't (about 95% of the time
they just won't boot right, and data to drive them is sparse /
nonexistent), they're useless. (Auto-iris goes bezerk, as does AF)
If they could be persuaded to work, either by cunning or by
replacing the entire electronics with something a little more
modern (the glassware can justify a substantially better resolution
than PAL, and imaging chips are cheap these days), they, coupled
to a Balloon, would make an exceptionally nice webcam.
>Are people interested in video grabber addons?
>If so what type(s) of input?
> e.g. PAL/NTSC, composite, SVHS, RGB, or other?
Does it matter? Don't most capture chips support all of these
(except maybe RGB)?
>Number of inputs?
Tricky... Depends what you imagine it doing - random stills,
streaming, or something else.
>Direct memory interface, or DMA type interface?
Again, tricky. The SA1110 doesn't expose any DMAs, so capturing
into a chunk of external memory is probably the best you can do,
with interrupts for new frame / field.
PXA does seem to support external DMA sources, but I'm not sure
it gains you anything except being able to run smaller external
buffers.
>Of course to do this requires mechanical format details and the
like, which
>I could not find easily on the site.
Should be in the gerbers. I've just prepared a drawing for 2.06,
but that's not on the web yet, since we've not confirmed that it
works. If you want a risky early set of gerbers, let me know.
Mounting Balloon is currently a hot topic. V2.06 and later have a
usable bare ring around the edge of the board, to allow it to be
slid into machined mounting blocks. This avoids any need to waste
real-estate on mounting holes which will inevitably be in the wrong
place for many users.
(That said, 2.06 does have 2 mounting holes. They're a massive
compromise, though, and their position is not promised to be
stable for future versions. Clamping the edge of the board is my
favoured solution into the future. (The ring around the edge is
grounded, both sides, and is appropriate for solder-tacking the
Balloon into a formed tin can, if you feel the need.))
I expect tin cans & plastic mounting blocks will be offered in due
course - probably by the first person / company to need them :)
Steve
,%20they're%20useless.%20(Auto-iris%20goes%20bezerk,%20as%20does%20AF)%0A>%20If%20they%20could%20be%20persuaded%20to%20work,%20either%20by%20cunning%20or%20by%20%0A>%20replacing%20the%20entire%20electronics%20with%20something%20a%20little%20more%20%0A>%20modern%20(the%20glassware%20can%20justify%20a%20substantially%20better%20resolution%20%0A>%20than%20PAL,%20and%20imaging%20chips%20are%20cheap%20these%20days),%20they,%20coupled%20%0A>%20to%20a%20Balloon,%20would%20make%20an%20exceptionally%20nice%20webcam.%20%0A>%20%0A>%20>Are%20people%20interested%20in%20video%20grabber%20addons?%0A>%20>If%20so%20what%20type(s)%20of%20input?%0A>%20>%20%20%20e.g.%20PAL/NTSC,%20composite,%20SVHS,%20RGB,%20or%20other?%0A>%20%0A>%20Does%20it%20matter?%20Don't%20most%20capture%20chips%20support%20all%20of%20these%20%0A>%20(except%20maybe%20RGB)?%0A>%20%0A>%20>Number%20of%20inputs?%0A>%20%0A>%20Tricky...%20Depends%20what%20you%20imagine%20it%20doing%20-%20random%20stills,%20%20%0A>%20streaming,%20or%20something%20else.%20%0A>%20%0A>%20>Direct%20memory%20interface,%20or%20DMA%20type%20interface?%0A>%20%0A>%20Again,%20tricky.%20The%20SA1110%20doesn't%20expose%20any%20DMAs,%20so%20capturing%20%0A>%20into%20a%20chunk%20of%20external%20memory%20is%20probably%20the%20best%20you%20can%20do,%20%0A>%20with%20interrupts%20for%20new%20frame%20/%20field.%20%0A>%20PXA%20does%20seem%20to%20support%20external%20DMA%20sources,%20but%20I'm%20not%20sure%20%0A>%20it%20gains%20you%20anything%20except%20being%20able%20to%20run%20smaller%20external%20%0A>%20buffers.%20%0A>%20%0A>%20>Of%20course%20to%20do%20this%20requires%20mechanical%20format%20details%20and%20the%20%0A>%20like,%20which%0A>%20>I%20could%20not%20find%20easily%20on%20the%20site.%0A>%20%0A>%20Should%20be%20in%20the%20gerbers.%20I've%20just%20prepared%20a%20drawing%20for%202.06,%20%0A>%20but%20that's%20not%20on%20the%20web%20yet,%20since%20we've%20not%20confirmed%20that%20it%20%0A>%20works.%20If%20you%20want%20a%20risky%20early%20set%20of%20gerbers,%20let%20me%20know.%20%0A>%20Mounting%20Balloon%20is%20currently%20a%20hot%20topic.%20V2.06%20and%20later%20have%20a%20%0A>%20usable%20bare%20ring%20around%20the%20edge%20of%20the%20board,%20to%20allow%20it%20to%20be%20%0A>%20slid%20into%20machined%20mounting%20blocks.%20This%20avoids%20any%20need%20to%20waste%20%0A>%20real-estate%20on%20mounting%20holes%20which%20will%20inevitably%20be%20in%20the%20wrong%20%0A>%20place%20for%20many%20users.%20%0A>%20(That%20said,%202.06%20does%20have%202%20mounting%20holes.%20They're%20a%20massive%20%0A>%20compromise,%20though,%20and%20their%20position%20is%20not%20promised%20to%20be%20%0A>%20stable%20for%20future%20versions.%20Clamping%20the%20edge%20of%20the%20board%20is%20my%20%0A>%20favoured%20solution%20into%20the%20future.%20(The%20ring%20around%20the%20edge%20is%20%0A>%20grounded,%20both%20sides,%20and%20is%20appropriate%20for%20solder-tacking%20the%20%0A>%20Balloon%20into%20a%20formed%20tin%20can,%20if%20you%20feel%20the%20need.))%0A>%20I%20expect%20tin%20cans%20&%20plastic%20mounting%20blocks%20will%20be%20offered%20in%20due%20%0A>%20course%20-%20probably%20by%20the%20first%20person%20/%20company%20to%20need%20them%20:)%0A>%20%0A>%20Steve%0A>%20%0A>%20%0A>%20%0A>%20%0A>%20%0A>%20 "Reply to this message")
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