[sane-devel] Brand New Day (PrimeFilm 1800i)

Bertrik Sikken bertrik@zonnet.nl
Mon, 11 Aug 2003 20:18:40 +0200

Alexander Feldman wrote:

> Thanks to Bertrik and Martijn for advising me to put a link with the
logs of
> my efforts to reverse engineer the protocol of the PrimeFilm 1800u
> slide scanner.
> The web page is:
> http://www.llama.gs/pf1800i/
> BTW, I have made a little progress today as I could start the step
motor and
> produced unpleasant sound when the scanner's head moved out of range.
Next I
> will make some more logs (scanning at max resolution an empty slide, 
> changing only one option to get the differences, etc.) and will try
> to
> some patterns in the log files.
> Can someone make an educated guess of what this scanner's protocol
> would look like? I don't believe these guys had created a unique
> protocol. Any documents of existing drivers? Pple's mind are good in
> finding
patterns but
> it is much easier with hints.

This definately looks like a parallel-over-USB protocol, used in
some canon scanners (630U) and some hewlett-packard scanners
(hp2300, hp3300, hp3400, hp4300).

For example, USB transfers with value=0x88 are used to send some
'magic' sequence to the scanner in order to activate it.

A genesys logic chip implements this protocol (maybe others too),
but as far as I know there is no 'official' documentation.
I think there is enough known about this chip already to bring
the USB transfer protocol down to a simple set of calls like:

There is already a perl-script somewhere that should be able
to reconstruct these higher level calls.

The hard part is figuring out what each register does.