[sane-devel] Backend for plustek Opticbook 3600

[Chris Berry]

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-front-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


-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

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