[sane-devel] Backend for plustek Opticbook 3600

[stef]

Le samedi 30 janvier 2010 15:29:50 Chris Berry, vous avez écrit :
> On 01/30/2010 01:40 PM, stef wrote:
> > Le jeudi 28 janvier 2010 11:26:56 Chris Berry, vous avez écrit :
> >> No stef im almost certain this isnt a Wolfson, from an old project page
> >> I think it is an Analog Digital 9826
> >>
> >> Link:
> >> http://www.analog.com/en/audiovideo-products/cameracamcorder-analog-fron
> >>t-e nds/ad9826/products/product.html
> >>
> >>
> >> I too am puzzled why there are so many writes to the frontend, the XP200
> >> in the gl686 I think uses an AD frontend and even that only has a few fe
> >> writes, although the XP200 has separate functions for AD coarse grain
> >> calibration and AD offset calibration so im not sure if these extra
> >> writes are done then? Any advice?
> >>
> >> Chris
> >
> > 	Hello,
> >
> > 	I had a quick look at the data-sheet. It is coherent with the writes you
> > see. One thing that I find strange is that bit 7 of register 0 is set to
> > 1, while it is recommended no to do so. Maybe it is a bug, or maybe your
> > scanner hasn't the same exact component.
> > 	During calibration there maybe a lots of writes to frontends. To go
> > further, I think it could be a good idea to have a test program to does a
> > simple color scan with a fixed area. You could code directly in it
> > various write to AFE until you get sensible data. I have appended the
> > main C file and the build file as a possible example.
> > 	I build like this make -DUNIT_TESTING&&  make -f mk .
> > The wm.c is how I experimented with HP3470's AFE.
> >
> > Regards,
> > 	Stef
> 
> Ok Stef, at the minute I have a separate function in gl841.c that is
> called during set_fe to skip the standard front end writes in that file
> and use the ones defined in my function. I have attached the function
> for you to look at.
> 
> My question is: is there any benefit to using the method you just
> recommended over the method im using now? If this function is required
> it is likely to implemented in the way i have so will it help me much to
> do what you have asked? Or is what i'm doing pretty similar.
> 
> Chris
> 
	Hello, 

	the function you wrote is fine. What I wanted to share is that it is easier 
to do experiments from within a really simple test program than the full blown 
scanimage or xsane.
	For instance, to get data from the HP3670, I had to set up registers that 
aren't set up under windows. I also found that I had to use different values 
for offset and gain than the ones that could found in usbsnoop logs.
	I think you'll need much trial and errors before having it work. You must 
also keep in mind that if GPIO aren't correctly set up, you may not get any 
data whatever you do with the AFE.

Regards,
	Stef