[lcd4linux] problem with i2c connected LCD display

[paul kamphuis]

Hi,

Is there anyone using lcd4linux in combination with an HD44780 based LCD
display connect via i2c bus?

I am using a PCF8574 i2c 8-bits IO extender to connect the LCD display.
The i2c is detect by i2cdetect on device id 26 (hex)

in lcd4linux.conf I have the following display definition:

Display HD44780-I2C {
Driver 'HD44780'
Bus 'i2c'
Port '/dev/i2c-0'
Device '0x26'
UseBusy '1'
Bits '4'
Size '16x2'
Wire {
RW 'DB4'
RS 'DB5'
ENABLE 'DB6'
GPO 'GND'
}
}

But when I run lcd4linux I get the following output:

Version 0.9.11 starting
lcd4linux.c: initializing driver HD44780-I2C {
lcd_init(HD44780-I2C {) failed: no such display

I tried different device id's (26, 38 ) to no effect. What is it I am
missing here?

Any help/suggestions appreciated

Paul

[Luis.F.Correia]

Hi!

-----Original Message-----
Sent: Wednesday, February 09, 2005 12:39 PM
Is there anyone using lcd4linux in combination with an
HD44780 based LCD
display connect via i2c bus?
I am using a PCF8574 i2c 8-bits IO extender to connect the
LCD display.
The i2c is detect by i2cdetect on device id 26 (hex)
Display HD44780-I2C {
Driver 'HD44780'
Bus 'i2c'
Port '/dev/i2c-0'
Device '0x26'
UseBusy '1'
Bits '4'
Size '16x2'
Wire {
RW 'DB4'
RS 'DB5'
ENABLE 'DB6'
GPO 'GND'
}
}
Version 0.9.11 starting
lcd4linux.c: initializing driver HD44780-I2C {
lcd_init(HD44780-I2C {) failed: no such display
I tried different device id's (26, 38 ) to no effect. What is it I am
missing here?
Any help/suggestions appreciated
Paul

I never got to finish the code I had done to support I2C under lcd4linux.
But beware, it is probably unusable as it is very very slow...
That is the main reason for my lack of interest on the project.

Luis

[Michael Reinelt]

Hi there,

I am willing to give it a shot, if you are prepared to
provide me with
some assistance on where to start and how to start. It would
be my first
effort on writing code on linux.

No problem, I'm not really a C expert but at least I can help you
to follow the 'good line'. :)

Hey, would be great if someone would work on this part! I can't be of
any help, because I don't have neither an I2C port on my notebook, nor
an I2c Interface. But I like the code from Luis, and I think we've got a
good framework for using HD44780 over two different busses.

The main reason for the i2c code not working is that most of the code is
#ifdef'ed out because I can't get it to compile. maybe some header or
something is missing.... I don't know.

Paul, the first thing you'll have to do is getting anonymous CVS access,
so you can work on the latest version of the source. If you need
assistance with CVS or anything other, please let me know.


bye, Michael