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[Lcdproc] ethlcd

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  • From: peter at (Peter Marschall)
  • Subject: [Lcdproc] ethlcd
  • Date: Wed, 17 Sep 2008 16:12:22 +0200

Hi Manio,

On Wednesday, 20. August 2008, manio wrote:
> First of all i need to write something about ethlcd. ethlcd is open
> source/harware a project which grow in my mind some time ago and now it
> is ready and blinking on my desk :)
> The HD44780 display is controlled via Atmel's ATmega microcontroller.
> There is also a ethernet chip (ENC28J60). So from lcdproc point of view
> a LCD is accessible via TCP socket. The device is powered via PoE, so to
> LCD display is only needed a UTP cable :)
> It has also a 6 buttons, backlight control and a beeper.
> Photos, schematics, pcb and more are on project homepage:
> Of course i wrote a driver - i was trying to preserve the rules in
> developer's documentation but now i realized, that one thing is shurely
> need to do - i have 3 global variables, which should be moved into
> driver's space. I've attached the diff against current CVS revision as a
> attachment to this message. Please look at it - i am open to any
> comments, especially from developers - i'll try to fix the code in the
> way you like. And after that i'll be very happy if there will be a
> possibility to merge it in CVS current tree :)
> Because of the hardware the driver is just another connection type of
> HD44780 - so it is written like for instance hd44780-ftdi and so - but
> it is called of course hd44780-ethlcd. Unfortunatelly - there is one
> thing to note: on my stable debian box it is unable to test the automake
> and autoconf when fetched from CVS. The debian's version differs from
> recomended - and i think this is the problem. The only SVN versions,
> which are compiling are nightly snapshots (with automake and autoconf
> done automagicaly) - so for now it is hard to test that aspect (automake
> and autoconf) of my diff file. Please also tell me how should be done
> the enabling of driver compilation - for now i've added the "if
> $enabled-ethlcd" but this test is performed in configure script - need
> it to be? - maybe just compile it like other hd44780 drivers - like
> 4bit, winamp or 8bit?

sorry for the late answer.

I have committed your driver to CVS with a few changes:
- "Device" as the key for the address in LCDd.conf.
If possible, I'd like to keep as little different
keys as possible.
Having a sperate key for the "device" of each connection type
doesn't help much I tink
- converted global variables in hd44780-ethlcd.c to members of
the ProvateData struct or removed them altogether.
- added the infrastructure for --disable-ethlcd
I was pondering making something like this for all of the
hd44780 connection types. So, I started with this one.
By default the connection type is included in hd44780,
but it can be left out at compile time.

The result compiles fine. Lacking the hardware I cannot test it.
Please test and report feedback.

A few suggestions for improvement.
- please have a look how server/drivers/hd44780-lcd2usb.c handles
brightnes and backlight.
This is the way it is done in various other drivers.
It offers more flexibility than completely turning off the
backlight (which sometimes makes displays unreadable)
- If you extend the documentation a bit, it does not hurt.
I added the short chapters for most non-parallel-port connections
in hd44780.docbook to have the other connection types at
least described a bit.
Having a real desciption that is come kind of counterpart
to the parallel-port connection types.

Thanks for supporting LCDproc

Peter Marschall
peter at

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