RE: [Lcd4linux-devel] I2C modifications to HD44780 driver

[Luis.F.Correia <Lui...@se...>]

Hi!
 

> -----Original Message-----
> From: Paul Kamphuis [mailto:pau...@xs...] 
> Sent: Wednesday, March 30, 2005 1:30 PM
> To: Luis.F.Correia; lcd4linux devel
> Subject: Re: [Lcd4linux-devel] I2C modifications to HD44780 driver
> 
> Hi Luis,
> 
> I found the problem. The wire configuration is not read 
> correctly from 
> the config file. It uses the default all the time. (and I have RS/RW 
> wired differently)
> This is how my display definition is constructed:
> 
> Display HD44780-I2C {
>     Driver 'HD44780'
>     Bus 'i2c'
>     Port '/dev/i2c-0'
>     Device '38'
>     Bits '4'
>     Size '16x2'
>     asc255bug 0
>     Icons 1
>     Wire {
>         RW     'DB4'
>         RS     'DB5'
>         ENABLE 'DB6'
>         GPO    'GND'
>     }
> }
> 
> Is that correct?

It seems to be ok, I'll have to make additional checks in order to see if
the values
are really read correctly. I just copy/pasted that piece of code from
another driver...

I can't make an actual test in any of my current development platforms, as
none has
a working I2C bus.

Luis Correia


> I noticed that the Section and Driver strings are allways 
> empty strings 
> in drv_generic_i2c.c is that correct?
> 
> thanks,
> 
> Paul
> 
> 
> Luis.F.Correia wrote:
> 
> >Hi Paul! 
> >
> >  
> >
> >>-----Original Message-----
> >>From: Paul Kamphuis [mailto:pau...@xs...] 
> >>Sent: Wednesday, March 30, 2005 8:01 AM
> >>To: Luis Correia; lcd4linux devel
> >>Subject: Re: [Lcd4linux-devel] I2C modifications to HD44780 driver
> >>
> >>Hi Luis and Michael,
> >>
> >>I did a check this morning. A 'normal' build doesn't enable the i2c 
> >>support as you both noticed. The reason for this is that in 
> >>the autoconf 
> >>phase of the build the include file linux/i2c-dev.h is not 
> >>detected as 
> >>valid. I am not sure of the reason but it has to do with the 
> >>way it is 
> >>validated by autoconf. I edited configure.in to return true 
> >>for the i2c 
> >>support even in the invalid case. It now builds nicely and 
> >>i2c support 
> >>is also enabled.
> >>Unfortunately doesn't work properly yet. I'll have to look 
> >>into it later 
> >>today. My guess is, that it has to do with the specification of the 
> >>ENABLE, RW, RS control signals. At least the observed 
> behaviour seems 
> >>similar to what I had initialy.
> >>
> >>    
> >>
> >
> >Well, all you will need to do is to create a setup similar to what is
> >in the lcd4linux.conf.sample, search for 'WRAP1C'.
> >
> >Copy that definition, edit where appropriate and it should work.
> >
> >You'll need to edit the i2c bus, the device address and where do
> >the signals go in terms of databus.
> >
> >However, if your 4 data pins do not correspond to the lower 
> 4 bus bits
> >(ie D0 - D3) then the code needs another rewrite, but it is doable.
> >
> >
> >  
> >
> >>Later today I should have some more time to test.
> >>
> >>Cheers,
> >>
> >>Paul
> >>
> >>    
> >>
> >
> >Tell me your thoughts on this!
> >
> >Luis Correia
> >
> >
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> >  
> >
> 
>