RE: [Lcd4linux-devel] RE: [lcd4linux] problem with i2c connected LCD display

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

Hi!

Just a small sidenote :

This diagram explains how it can be implemented.
http://secure.netroedge.com/~lm78/docs.html

Luis

> -----Original Message-----
> From: Luis.F.Correia [mailto:Lui...@se...] 
> Sent: Friday, February 11, 2005 12:10 PM
> To: lcd...@li...
> Subject: RE: [Lcd4linux-devel] RE: [lcd4linux] problem with 
> i2c connected LCD display
> 
> Hi!
> 
> Please do not post HTML or Rich-Text to this mailing list. It 
> is annoying!
> 
> 
> >From: paul kamphuis [mailto:pau...@xs...] 
> >Sent: Friday, February 11, 2005 11:39 AM
> >To: lcd...@li...
> >Subject: Re: [Lcd4linux-devel] RE: [lcd4linux] problem with 
> i2c connected
> LCD display
> >
> >	Thanks for the answers.
> >	
> >	If I understand correctly there is no longer a 
> userspace layer for
> the i2c 
> >	interface. (or at least not supposed to be) 
> >
> 	 
> Wrong, there is a userspace layer!!! What is not suppose to 
> happen is we
> communicate
> with the hardware directly. (kernel space)
> 
> You must use the I2C infrastructure as is provided by the i2c project.
> Start here: http://secure.netroedge.com/~lm78/download.html
> 
> If you are using any 2.6 kernel you will not need the 
> i2c-2.9.0 package.
> 
> Now try to compile i2c against your kernel sources, but 
> without patching the
> kernel.
> Then load the appropriate i2c modules that support your bus 
> type. Load the
> PCF7584
> module and try to access it (read/write via /sys interface).
> 
> If you can access it, try to write some values and see if the 
> chip pins
> reflect those
> values.
> 
> If all goes ok, then start to investigate how to access it 
> programaticly
> from the i2c
> API.	 
> 	 
> 	 
> >	If I understand the pcf8574 kernel module correctly. Is 
> this no more
> then a wrapper 
> >	around these i2c_smb functions. So it can't be much slower then
> calling them directly.
> >	The main advantage of this concept it that all (byte) 
> devices have
> these read and 
> >	write files. So you could use any device available.
> >	
> >	So for a start, I give the pcf8574 a try. Shouldn't 
> take to long to
> test.
> >	Lets see if you are right that it is too slow. ;-) 
> >	
> >	Paul
> 	
> 	
> Best of luck!
> 
> Luis
> 
> 
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