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View Full Version : Video-Cam for XDA?

04-30-2003, 06:17 PM
There are any Cam for XDA that i can plug somewhere?
If there isn't any, why not? It's impossible?

Jason Dunn
04-30-2003, 06:49 PM
There are SD cameras coming, but I don't think they're shipping yet. Further, the SD slot on the XDA isn't SDIO as far as I know, which means you couldn't use the SD camera anyway (unfortunately).

04-30-2003, 08:45 PM
I'm just curious about this SDIO thing.
Since non-SDIO PocketPCs can obviously read SD cards, and since a picture is just a bunch of bytes accessed from an area of memory, why can't a camera dump its image to an area of an SD card which to the PocketPC looks just like another piece of memory?
OK, so it would have to be a reserved area of memory, but software could easily take care of that.
I just can't see why it would be impossible to create a camera (at least a still camera) that could work with any SD slot.
As you can tell, I'm no SD expert, but what am I missing here?

04-30-2003, 11:27 PM
Unlike the mini cams that are attached to cell phones (though the trend is moving to one piece phone cameras) where the camera has a click button and then sends the data to the phone memory, these CF and SD cameras are controlled by the PocketPC unit.

The SD slot must be capable of input (directions to take picture, etc.) and output (sending the picture data to memory).

Memory cards do not require this.


05-01-2003, 09:43 AM
Sorry to be a dog with a bone, but SD is a bi-directional medium. You can not only read memory from the SD card, but you can write it as well.
I'm probably revealing my age here, but back in the old days, the way you would get things to happen on a micro would be to POKE some data into a special reserved memory location, and that would be interpreted by some hardware as being a directive to do something.
My point is that as far as I can tell, the PocketPC doesn't need to treat an SD Camera as being different from an SD Memory card. Sure, with a special interface things might be easier, but on the other hand by not using SDIO, the camera would work in a greater range of devices.

05-03-2003, 12:42 PM
i think youre reasoning is correct.

im just guessing here but i think the problem is just the bandwidth to the card, and possibly effeciency of the i/o driver for sdio.

from other threads i have read that transfer speed with plain sd is much slower than sdio because sd supports a singe bit bus while sdio is 4 bit.

it speed is the issue, then the camera would need to have its own memory to act as a cache while the data is being transferred to the ppc.
but.... it just occurred to me that some stand alone camera's use only sd cards for memory. i dont know if they have sd or sdio though. im too lazy to search the forums right now but there were several threads on cameras for the xda...

Janak Parekh
05-03-2003, 04:01 PM
onepieceman, your idea of having a memory-mapped SD camera (i.e., a SD camera that appears as memory to the Pocket PC) is interesting, but it's not good enough, unfortunately. Say the camera streams 15 frames per second when its active -- is it supposed to update a file 15 times per second? File systems aren't efficient for streaming applications like that; and they don't provide convenient control channels (i.e., exposure) either.

That said, it might be interesting to try. But, it's not likely to happen anytime soon, and your best bet would be to get a compact camera that uses SD memory cards. The Casio Exilim (exilim.casio.com) is one.