[cpia] ECP transfer of data

[Peter Pregler]

On Fri, Feb 22, 2002 at 03:58:36PM -0000, J114(G.M.REYNOLDS) wrote:
> 
> I then attempt to clock data in from the camera.  All control lines change
> appropriately and it appears that data is coming in. However, the only value
> on the port is 0xFF.
> 
> Answers to the following questions would help me:
> 1. Is the initialisation sequence critical? I have followed it according to
> datasheet.
> 2. I have attempted to use the StartDummyStream command to get back data. It
> also sends 0xFFs.

I have never used the dummy-stream. But the 0xFF rings some bell. IIRC,
the chip will _always_ provide you with 0xFF if you read and there is
no data available. So double-check if you really have done the
initialisation correctly. Sequence and even timings between sending
commands does matter. Just have a look at the stream-read (i.e. the
non-dma code) in cpia_pp.c.

> Are there any more datasheets for the camera available?

There is full chip documentation including the windows driver available
at webcam.sourceforge.net. What more do you want?!

Good luck, Peter

-- 
Feeling amorous, she looked under the sheets and cried, "Oh, no,
it's Microsoft!"
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Email: Peter_Pregler@email.com