[sane-devel] gl843 & genesys backend

Pierre Willenbrock pierre at pirsoft.dnsalias.org
Tue Mar 27 21:25:49 CET 2007

Hi Igncio,

J. Ignacio Gijón schrieb:
>  Sorry if you receive this message twice, I sent a similar one
> yesterday but it looks
> like it is lost.

It is right there.

>  My question es about the HP G4050 scanner that uses a gl843 chip. I
> have had
> one of this for a couple of weeks now, and have been playing a bit with the
> genesys backend and some captures with an usb sniffer.
>  The chips I've been able to identify in this scanner are:
> Usb chip: gl843
> Motor: allegro a3967 slbt
> AFE: wolfson   WM8196 scds
> Memory: atmel 628 93c46
>  I've done some changes to the gl841 part of the genesys backen to
> initialize
> the extra registers of the gl843, change the way the motor tables are
> loaded
> (different to the gl841) and all the things I've found that need to be
> changed
> in some hours reading the genesys code.
>  Right now I have basic communication with the scanner, but the motor moves
> very slow, I've read several messages in the archives of the list
> about the configuration of the structures of the genesys backend and I
> think that the configuration is more or less ok. And I'm not able to
> get a image although
> I don't see errors in the logs (SANE_DEBUG_GENESYS_GL841=255)

A moving motor is a good first step, that means the gl843 is basically
doing it's job as instructed, and the hardware does not have too special
power management features(ever needed to switch gpio pins in a certain
order, else the scanner shortcircuits itself and resets?).

What you are running into is the complete lack of ccd-support in the
gl841 part. Currently, only cis-mode is implemented. You need to collect
the register settings for the clock registers, setup the lamp pwm
properly and set the scanner into ccd-mode. If i didn't forget some
part, that is.

>  Probably the motor and the gpio parts are wrong.

don't worry with the motor. that should be easy to improve.

>  So my question is, have somebody done something to support the gl843? I've
> read somethings in the archives about some canon scanners using this
> chip, but
> have found nothing to look.

To my knowledge, there is no previous work for the gl843.


More information about the sane-devel mailing list