[sane-devel] mustek_usb2 SQ113 Tevion MD 90070

[Christian Schmitt]

Hi Jan,

thank you very much indeed for those information. Your git repo is exactly 
what I have been looking for. I already compiled it but had some issues, 
which I need fix first. Sent you a private mail already, too.

I'm glad to see the amount of work you already put into the mustek_usb2 
sources. Will try to get it running here, too.

Chris

Jan Hauffa wrote:

> A year ago, I was in the same situation as you: I had just bought a
> Medion MD90093 (USB product ID 0x3025, same as the MD90100), found out
> it was using the SQ113 chip, and tried to make it work with the
> mustek_usb2 backend. There are two issues with this approach:
> 
> 1) The SQ113 is a rather primitive chip. As you can see from the
> (otherwise mostly useless) data sheet [1], it is basically a USB
> interface to a 8031 CPU with some ROM and RAM, which in turn
> communicates with a number of external components: SDRAM for buffering
> image data, a motor driver, and a CCD sensor. This is convenient for the
> manufacturer, as they can just throw together whatever components they
> can get cheaply, but highly inconvenient for us, as a driver for a
> specific SQ113-based scanner is unlikely to work for another model with
> a different set of external components. Even worse, the communication
> protocol is mostly determined by the firmware, and so far I've seen
> three different firmware variants "in the wild".
> 
> 2) The mustek_usb2 backend is a mess, it contains lots of dead code and
> copy & pasted code with subtle differences between the copies. Also, it
> has been written specifically for the "Mustek BearPaw 2448 TA Pro", and
> its design does not lend itself to adding support for different motor
> drivers, CCDs, etc.
> 
> I've done a lot of refactoring on the mustek_usb2 backend, but so far I
> have been unable to test it for regressions with an actual BearPaw 2448
> TA Pro. Recently I have acquired one of these scanners, but it has a
> mechanical defect which I have to fix before I can run any tests.
> 
> Furthermore, I've logged some of the USB traffic between the Windows
> driver and the MD90093, and attempted to modify the backend accordingly.
> Motor movement appears to work, but the CCD parameters are not yet set
> correctly.
> 
> I've published the code on github [2], it might be useful for you if you
> decide to use the mustek_usb2 backend as a base. I'm enthusiastic about
> making this scanner work with SANE, but unfortunately I really lack free
> time to work on this project. However, feel free to contact me off-list
> if you have any questions.
> 
> Best regards,
>   Jan
> 
> 
> [1] http://yc-dz.com/productimages/11477678.pdf
> [2] https://github.com/jhauffa/sane-sq113
> 
>