Re: [lcd4linux] 3x HD44780 problem / special character problem

[Michael R. <re...@eu...>]

Hi Kamil,

> after evaluating lcdproc, lcdmod, lcd-linux and lcd4linux I found=20
> lcd4linux the fastet and most sophisticated LCD driving application
> of all of them. I especially like the softwiring, nevertheless I used
> "WinAmp" style wiring the way lcdproc understands and soft-wired
> these settings in lcd4linux.conf.

Thanks a lot!

> Then I got high-spirited and tried to wire up a third 20x4 HD
> compatible LCD. In order to do so I salvaged the the third enable
> line (EN3) by disconnecting R/W from the 40x4 ( and connecting that
> to GND ). The 40x4 share the RS line,
all three displays should share the RS line!

> both have D0-D7 connected and each controller ( 2 on the 40x4 / 1 on
> the 20x4 right ? ) has its own enable line.
Correct.

>=20
> I configured the whole thing like this :
>=20
> Display HD44780-40x8 { Driver      'HD44780' Model       'generic'=20
> UseBusy     0 Bits        '8' Port        '/dev/parport0'
>=20
> Controllers 3
>=20
> Size        '40x8' Size1       '40x2' Size2       '40x2' Size3
> '20x4'
You can omit the 'size' parameter (IIRC) because LCD4Linux automatically
 sums up the individual sizes.

>=20
> Wire { RS          'INIT' RW          'GND' ENABLE      'STROBE'=20
> ENABLE2     'SLCTIN' ENABLE3    'AUTOFD' BACKLIGHT   'GND' GPO
> 'GND' POWER       'GND'
>=20
> } }
>=20
> Is this correct, theoretically ?
Looks very correct to me. Although I must say that I've never used more
than one display... geronet?

> I believe so, but the practical result proves me wrong. The 20x4
> won't even intialize. I only see two lines of blocks. I can't be
> completely sure, that the 20x4 display isn't broken since it isn't
> new but an older one salvaged from a display project some time ago.
Yopu got two lines of blocks? Normally there should be only one (or line
1 & 3 on a 4-line display). This is how the display tells you "I'm ready
for being initialized".

Maybe it's a contrast problem? There are displays out there which have a
good contrast with the contrast hardwired to GND; but others really
require a resistor (or better a potentiometer). This would explain the
two black bars, too.

Did you try to remove the enable lines of the other displays, and
connect the enable of your third display to one of the others?


> The second issue is the usage of the i2c plugin. It's a great plugin
> and I emerged lm_sensors to feed it properly. Again, it's working out
> of the box using the example provided.
>=20
> Since I sit in Germany and I like our =B0C trailing any temp degree
> value I wanted to add a postfix to get something like CPU: 34=B0C.
> After doing so my whole layout got screwed up. I searched the
> archives and found something about using \337 the octal value of the
> ASCII character, but that didn't work out as well.

Are you sure that your display has the degree char has 0337? I think the
octal stuff should work, although I'm not sure (I'm in the office at the
moment, and therefore cannot test). You could try any other ASCII value
(maybe just an 'a') just to make sure this works...


bye, Michael

--=20
Michael Reinelt <re...@eu...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781