634 Not working with LCDproc


New member
I just got my 634 Intelligent 2.0 inverted yada yada today. Plugged the cable into the display, the other end into the serial port, fired up LCDproc.... nothing...

Here's the driver section of my /etc/LCDd.conf

# CrystalFontz driver

# Select the output device to use [/dev/lcd]

# Select the LCD type (size) [20x4]

# Set the initial contrast [140]

# The backlight brightness settings are retrieved
# from the serversection now. And can therefore be
# modified from the server menu now.

# Set the communication speed [9600]
# possible values: 1200, 2400, 4800, 9600, 19200

# Set the firmware version (New means >= 2.0) [no]
# if set, set Speed to 19200

# Reinitialize the LCD's BIOS [no]
# normally you shouldn't need this

I've tried setting it to /dev/tty0 as well, same thing. I'm using the CVS version of LCDproc and I;'ve used it fine with an HD44780 VFD. So what's wrong?

I measured -12v across pins 5 (GND) and 7(live). Is -12v correct??? Anyway, what's wrong? THanks!
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New member
I'll preempt the anticipated response and say that I just connected it to my Windows XP laptop and ran CrystalControl on it. It doesn't give me any errors but it doesn't display anything either.


New member
Fine, make a liar out of me. The control program in Windows XP, when the contrast is set to 100%, and when TEST SETTINGS is pressed causes the CrystalFOntz screen to flash for s plit second, and them all the pixels light up, althought this is all very faint. I measure -5v across the terminals on my laptop... What's going on here?
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New member
Okay, you know how sometimes you can talk yourself through things and then you feel like a real tool? Yeah...

Okay, my problem with LCDproc was that I was sending the data to /dev/tty0 instead of /dev/ttyS0. I thought something didn't look right...

Okay, I still have some problems. First of all, the inverted display is pretty difficult to read. I suppose connecting the backlight will solve that?

Also, when I'm running LCDproc clients, rather than displaying a whole "block" when required (i.e. for equalizers and the like) it displays the } character instead. I'd like to cure this, and also get an answer to my question about connecting the LCD to the accessory line of the car. Can I just switch the - and + wires when connecting them to the display? Would this provide me with -12VDC or would it fry my display? Thanks!


New member
All right, all right, flame away...

The character problem was because I set the firmware option to "new" rather than "yes" as it should be. Well, looks like posting to this forum was a great idea! All my problems were solved! Now I have another issue that I'm going to make a new thread for...