[sane-devel] genesys backend

[Brian J Densmore]

Pierre Willenbrock wrote:

>Brian J Densmore schrieb:
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>>Pierre Willenbrock wrote:
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>I did a major restructuring on the gl841 part. You may want to take a
>look at that.
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Are you referring to the patch you created? I've already applied that.

>Essentially to add support for a gl841/gl842 based scanner you need to
>find out the motor acceleration curve and type(half-step, quarter step
>capable), ccd settings and analog frontend settings.
>
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Well as for the motor acceleration, I'm not sure I need to do anything 
there except
use the code that the Medion 6228 uses. At least for resolution up to 
2400 xdpi.
I'm currently building a Windows machine with USB support so I can do some
USB sniffing. I am still trying to get the datasheet for the GL843, I am 
hopeful
of getting that from a tech at genesys soon. I'm sure the registers are 
different
from the 842. Also the 8400 is eighth step capable.

>All of these can be obtained from an usb sniffer log, captured while the
>windows driver calibrates the scanner. I can help analyzing a sniffusb log.
>
>You will find the ccd settings struct to be missing the gl841 ccd clock
>settings. My scanner didn't need them, so i didn't add them. Just add
>more fields there, as needed.
>
>Transparent adapter support is completely missing.
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Any ideas on where I could steal some code from to try to make work. 
I've seen the
registers in the 842 specs that need to be populated. If you'd like I 
could work
on adding that to the existing scanners. Not sure if any of them are 
capable.

>We will need to add support for horizontal resolutions which do not
>directly map to one of the gl841 settings(600, 1200, 2400dpi). Using
>these settings the chip decides which memory layout to use, and how to
>treat the dpiset setting. Technically, in 2400dpi mode you can equip the
>scanner with a 43690 pixel ccd with arbitrary resolution, in 1200dpi
>mode half of that.
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I noticed you were using a 'non-supported' resolution on the LiDE. Why 
not not just use the
resolutions that the GL84x are designed for? There is also the 
possibility of using the deletion
type bit in the AVEENB register (bit 6 of reg 3)? That is the one you 
were talking about
right? The 842 chip should have 1200,600,400,300,200,150,120,80 for a 
1200 xdpi scanner,
by setting registers 44 and 45 (0x2C, 0x2D) and clearing the AVEENB bit. 
I don't know
what the bit settings are for those resolutions though. They aren't 
defined in the spec, that I can see.

Thanks,

Brian JD