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> Hardware/assembler Questions, devel of a composite video interface
vume5
post Sep 17 2005, 05:46 AM
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Hello,
I'm looking for a high-res PDA (like the Cxx0, for example) whose screen I can use as a camera output-screen.
Since (according to my research) there are no PDA-cams available that use the full VGA resolution in Live-Preview-Mode,
I'm currently considering building an adapter for Composite-Video sources and writing the appropriate driver or "OS"(made exclusively and specifically for this task, of course).
The hardware part wouldn't be an issue: There are cheap ICs which convert composite to RGB or YCrCb. Specifically, I found the ADV7181B which outputs 16 bits pixinfo(YCrCb) @ 13.5MHz.
Can the CF-interface handle such an input? If, as I expect, it can't, then I'll need another chip as buffer/interface ....
I couldn't find any info which CF-standard the Cxx0s support.
Do they support CF+/2.0 or even CF3.0?
To achieve 25 fps (may be less) at 640x480 pixels, a transfer rate of 15MB/s and thus at least CF+/2.0 (16MB/s) is needed.
PS: Does the videomemory/framebuffer have RGB format? If so, how are the 16bits divided among the 3 colors (which one gets an extra bit)?

The main problem of such a project would be the development of the driver / the OS, primarily because hobby programmers usually don't get access to the docu they'd need for such devices like PDAs.
For example, I'd need know how I can (via assembler) receive the data from the interface and write it to the appropriate video memory location.
However, on a Linux PDA, this shouldn't be too much of a problem, since the OS source code is available. In fact, there are (to my knowledge) three alternatives:
-Freescale BSP from Metroworks (any idea which one I'd need?)
-OPIE
-GPE
Any recommendations?


greetings,
aha
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speculatrix
post Sep 30 2005, 02:06 PM
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there's been a discussion on the 1000/3x00 boards about adding video out, using a hacked interface through the CF slot by adding extra connections from CPU to a 2700 video chip.

meanwhile, if you can find the full tech sheet for the ATI w100 lcd/video controller, you might find a way of getting a useful video stream from the 700/760/860, and recoding it into analogue video?
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vume5
post Oct 1 2005, 10:37 AM
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"I'm looking for a high-res PDA (like the Cxx0, for example) whose screen I can use as a camera output-screen."
So, the idea is to use the PDA-screen, not an external one.
I want to connect a cam to the PDA and view on the PDA what the cam is showing, which means I need Video-In, not Video-Out.
Application: similar to rear-view parking-aid cam-TFT-combos, except that I want to use it to look around sharp corners without having to infringe upon the main street.
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