[sane-devel] HP 4570c - progress report

[Bertrik Sikken]

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Daniel Franke wrote:
> On Wednesday 14 September 2005 21:41, Bertrik Sikken wrote:
> 
> 
>>>On Tue, Sep 13, 2005 at 07:36:19PM +0200, Bertrik Sikken wrote:
>>>
>>>>The protocol is weird because it seems to implement some kind of
>>>>'USB-over-USB', i.e. the data payload of the USB control packets
>>>>looks like another USB control packet. The payload size never
>>>>appears to exceed 8 bytes.
>>
>>[snip]
>>
>>The more I look at the usbsnoopy log, the more it looks similar
>>to the hp5400 backend. This is probably good news because the
>>hp5400 accepts a limited set of commands instead of dozens of
>>writes to various registers.
> 
> 
> 
> Bertrik, Henning,
> 
> I managed to reliably pass some bytes between my test program and 
> the scanner. 
> 
> Already working: 
>  * an answer to 0x1200 (version information of HP 5400 -- "SILITEKIElwood")
>  * re-read the last command (0xc500, same as HP 5400)

Cool. :D.

> An observation: 
> Each command sequence has to be "terminated" by a null-byte, otherwise 
> communication gets out of sync. A command sequence looks like ...
>   - set up and write a "usb_ctrl_setup"-structure (defined in <usb.h>)
>   - read the answer
>   - send another '\0' to the device
> 
> Does this look familiar? 

No, does not look familiar to me, sorry.

> Are there any other known HP5400 command bytes I could give a try?

Have a look at the #defines in backend/hp5400_internal.h from the
sane-backends package.

A very cool thing to start with, is to try to switch the scanner
lamp on or off. As far as I can tell from the hp5400 backend, this
can be done with command 0x1BXX.
By the way: some scanners are not protected from moving the carriage
beyond their physical limits. This may result in a loud (clicking)
noise and possibly damage the scanner. So always stay close to the
scanner to quickly yank the scanners' power cord in case that
happens.

All the best,
Bertrik



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