634 USB and crystalcontrol problem


New member
hello there...

i m having hard time trying to get the program working with this screen
i installed the driver and virfied the com port used and tryed other freeware software everything working fine execpt the main software

when running crystalcontrol i can adjuct com port and when trying to select module setup it give this massege

( access violation at address 04A2BDC in module 'crystalcontrol.exe' read of adress 00000000 ) !!!!!!!!

what can i do to solve this ????

btw i have XP pro SP1 installed
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New member
I've just recently started having this same problem (Win2k w/ all service packs installed). It repeatedly opens this error message over and over. It happens with every single version of Crystal Control I try. Uninstall, reinstall, reboot, same thing. I tried using another program mentioned here in the forums, and that program did the same thing, but then the error message popped up so many times and so freaking fast that I couldnt click them off quick enough and had to hit my reset button. Any ideas, because I'm all out...
USB LCD Displays - Graphic and Character LCDs with a Keypad


New member
No takers eh? *sigh* Meanwhile, my $100+ 634 is occupying 2 of my drive bays being useless at the moment. I'm not willing to go the route of formatting because of one program. I guess someone on ebay is going to get one heck of a deal...

CF Support

If CrystalControl isn't working for you, please bear in mind that it's not the only software that supports the 634.

There is always any of the above:
Jalcds: http://www.jalcds.de/
LCD Smartie: http://backupteam.gamepoint.net/smartie/
LCD Max: http://www.coldcpu.de/LCDMax/
LCDriver: http://lcdriver.pointofnoreturn.org/index.html
LCD Studio: http://www.lcdstudio.com/e107/download.php

And many others. Don't let a hang-up with your system and CC be a deciding factor on whether or not you're happy with your 634. ;)


New member
Thank you for the links to the other software. I had problems with them all (and i can never get a link to LCDmax to work), except Lcd Studio, which I have running now. Although I like Cyrstal Control a lot better, and It seems to be more user friendly, at least my 634 is up and running again. :)

CF Mark

Sorry for the delayed response.....

It wont be the IO driver thats causing this problem as it is only used when a HD44780 LCD is used (im not sure if this is the case with other software though).

The error occours when CrystalControl cant open the COM port youve specified in the options.

First try removing the whole CrystalControl settings from the registry by running regedit and deleting the key "HKEY_CURRENT_USER\Software\CrystalControl".
The next time you run CrystalControl, itll then have no settings and start up ok.

If you have a USB LCD and are sure you have the COM port setup correctly, you might be experiencing a problem with the USB drivers where sometimes the USB LCD doesnt get detected/start-up during windows boot.
If this is the case, then the LCD will need to be un-plugged and plugged back in before you can start CrystalControl.
Yes, this is a very annoying thig to have to do... but for the moment there is no known fix.