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Thanks a lot of good tips there .<br>
<br>
I know that it's not a "let's do a scanner driver thing tonight" thing
and can take some time and efforts. Thanks again for the little push
ahead !<br>
<br>
Marco<br>
<br>
m. allan noah schrieb:
<blockquote
cite="mid:97246d0e0801051056s22d00cd1yc63bd6e24067ce9b@mail.gmail.com"
type="cite">
<pre wrap="">On 1/5/08, Marco Freudenberger <a class="moz-txt-link-rfc2396E" href="mailto:Marco.Freudenberger@gmx.de"><Marco.Freudenberger@gmx.de></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi list ....
I'm urgently looking for a backend driver for a Plustek PL 812 (USB /
ADF + Flatbed) scanner. Looks like there's (bu-huuuu) currently no
backend that supports it.
</pre>
</blockquote>
<pre wrap=""><!---->
[snip]
</pre>
<blockquote type="cite">
<pre wrap="">But it would be great if somebody could help me alittle to bring me on
speed making the first baby steps. I plan to use a USB sniffer
(hardware) on the PL-812 on Windows to try to reverse engineer the
protocol. I don't think this will be the worst part. But actually, I
don't know where to start with developing and have a few questions to
the more experienced guys out there:
1) the backend-writing doc
(<a class="moz-txt-link-freetext" href="http://www.sane-project.org/backend-writing.txt">http://www.sane-project.org/backend-writing.txt</a>) suggest to start with
a standalone test programm. Is there some kind of a framework or
existing test programm that can be modified for starting ?
</pre>
</blockquote>
<pre wrap=""><!---->
if you use benoit's usbsnoop instead of a hardware sniffer, there is a
program (usbsnoop2libusb) which will turn that into a c prog that you
can hack on. it cannot interpret the meaning of the packets, but it
can be a good place to start. there are also programs in the usbsnoop
dir of the sane experimental tree, which can clean up logs from
usbsnoop as well. i am fond of spike4.pl myself :)
</pre>
<blockquote type="cite">
<pre wrap="">2) the same document suggest (sounds like a good plan!) to extend
existing backends whenever possible or use existing backends as a
starting point at least. Any idea which one could be a good starting
point for the PL-812 ?
</pre>
</blockquote>
<pre wrap=""><!---->
open the scanner and figure out what chips are in it. it may already
be supported by an existing backend, just needs some tweaks to know
about that model.
</pre>
<blockquote type="cite">
<pre wrap="">3) Is there any further documentation out there to get me on speed ? Or
books on that subject-matter (also the relevant parts of Unix / USB
programming that might be needed) ?
</pre>
</blockquote>
<pre wrap=""><!---->
google for 'usb in a nutshell', and the usb 1.1 specs. the libusb docs
are almost useless.
</pre>
<blockquote type="cite">
<pre wrap="">4) What is an ususal ammount of time one would plan for developing a
backend for a certain scanner ?
</pre>
</blockquote>
<pre wrap=""><!---->
>from a couple hours if it is an already supported chip, to hundreds of
hours if it is completely new and you have no docs.
</pre>
<blockquote type="cite">
<pre wrap="">5) BTW, my environment will be a Kubuntu Linux distribution. Anything
special about that ?
</pre>
</blockquote>
<pre wrap=""><!---->
nope, as long as you install the libusb devel headers and gcc, you
should be good.
</pre>
<blockquote type="cite">
<pre wrap="">Thanks for your help! I know, those questions sound like I will never
make that happen in a reasonable ammount of time, but once I know where
to start that will change - I'm really a good and incredible quick
developer, usually ...
</pre>
</blockquote>
<pre wrap=""><!---->
i used to say the same thing, until i developed the epjitsu backend
with no docs. i dont know if i will ever do that again... :)
allan
</pre>
</blockquote>
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