On Wed, Jun 13, 2012 at 5:17 PM, Matti Viljanen <matti.viljanen at wippies.com> wrote: > Hi, > > For a few days I've tried to extend scanbuttond to include also the value > that's displayed in the little LCD panel in my HP ScanJet 5590 > (by making scanbuttond run the script with one more arg). Does anyone know > how it's supposed to be read?
Hi, Matti! As far as I understand, the LCD isn't controlled by device driver or backend, rather the controller/firmware simply reacts on Up/Down buttons press and increments/decrements the value displayed. So, you need to handle button press events and store the resulting value. > According to sane backend 'hp5590' source, the devices EEPROM must be read. > Comparing with reading button status, how different an operation this is? > All I get is usbfs error lines (ret -110 --> timeout) although I believe the > code is identical... > Has anyone actually gotten the value out correctly? Well, there is a function to read all EEPROM from the device (see backends/hp5590_read_eeprom_all_cmd.c from SANE sources) - might be an interesting idea to read the contents upon receiving an event from buttons, we might find something being stored there. My wild guess is that LCD connected to a GPIO of controller and firmware just handles it internally. Unfortunately, original Windows driver has shown nothing (or I didn't notice) revealing any interface to that. -- ?Ilia Sotnikov
