plustek: adding support for additional lm983x based scanners
Subject:
Re: adding support for additional lm983x based scanners
From:
"Allan N. Hessenflow" ####@####.####
Date:
30 Jan 2002 04:54:47 -0000
Message-Id: <20020130045104.A6339@kallisti.com>
> This Epson 1250U is turning into a bit of a pain. In terms of
> hacking up an improvement, I'm blowing it big time.
>
> Currently I can do the motions of a preview scan IF I don't
> select much more than the default 50dpi. The only recovered data
> is in the red channel, and I can trade the channel orders around
> (rgb,bgr,rbg, etc) with absolutely no effect on the recovered
> data. What little data there is stays in the red, with greeen
> and blue being effectively a flat, 100% field except for a couple
> of horizontal streaks in the upper 1/4 of the scan. It looks to
> be very badly bleached.
Assuming this isn't some artifact of the calibration generating very
bad curves, it sounds like the Epson 1250U must have its CCD hooked up
to the lm9832 in the same way as the Umax 3420. I'm getting results
just like that. I intend to start recording the actual register settings
and raw image data, during calibration and scanning, in the hopes that
I'll get some idea what is going on, but haven't had time to do that just
yet. I was really hoping someone on this list would have run into this
and actually tracked it down before, but it doesn't look like it...
> It also doesn't shut the lamp off at quitting time, and only
> turns it on about 2 or 3 seconds before it moves out of what I
> assume is the calibrate position, many seconds after clicking the
> scan start button.
I can't think of anything that would change at that time that might
activate the lamp. Assuming the lamp is on one of the misc io pins,
you might try searching through the code for all of the accesses to
the misc io control registers to see if it looks like any of them
might change state around that time. Or, you might try just changing
the initial state of any of the misc io pins that are outputs (in
plustek-devs.c) to see if one of those changes causes the lamp to turn
on immediately when you start a sane client.
> Are there any good linux tools to take one of these things apart
> and make readable .ini or .txt files out of whatever compression
> format billies children are using this week? It sure seems to me
> there ought to be some clues somewhere in that 50 megs of freebie
> stuff.
The .ini file should certainly have some useful information in it, but
it probably won't give any clues about the image data - I haven't seen
anything helpful in the .ini file for the Umax. There actually may be one
clue - the ini file shows some strange values for the lampb control, that
if I understand them correctly are causing it to pulse for a fairly short
time near the beginning of every line. I think I've duplicated that in the
plustek driver, but it hasn't helped. Maybe those parameters only apply
to a different scanning mode than I'm actually trying. What would probably
help would be to find a windows machine to try it on and logging the usb
transactions while getting a scan started, but that's not something I can
conveniently setup (and wouldn't know what to use on Windows to do that sort
of logging anyway).
allan
--
Allan N. Hessenflow ####@####.####
