New member
I got the CFA634-TMC-KS w/ USB connector. I setup and install the usb drivers and i can see the blue backlight. But when i start Crystalcontrol and press "Add a New Screen" a error message pops up

'Access violation at address 0049F234 in module 'CrystalControl.exe' Read of Address 00000000'

I cant display anything on my LCD.

1 more question when I go to 'Configure Module' what should the settings be if im using usb?
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CF Mark

You must add and configure the module before adding screens for that module.

Check the windows device manager for the COM port number that the USB driver is using.

In the module confing, use the 634, com port of the one used by the driver, speed of 19200.


New member
Yes i set the thing to COM3 and 19200 baud rate. But Whenever i press the Add New Screen Button it says

'Access violation at address 0049F234 in module 'CrystalControl.exe' Read of Address 00000000'

Then i enter the Add New Screen page and enter test lines to be displayed on the LCD. And when i press done theres nothing In green box of crystalcontrol.

WHat i think is the problem is something in crystalcontrol.exe, like the error message above.

I have WINXP PRO. PLz Help or i might have to return it.

CF Tech

Here are a couple of things to try:

1) Make sure the LCD shows up in your device manager under "Ports (COM & LPT)", and that there is no yellow warning flag on it.

2) Make sure te COM port shown in the device manager matches the COM port selected in the application.

3) Use WinTest to make sure everything is going correctly (exit CrystalControl before running WinTest), then once you know the LCD and driver are working, dive into CrystalControl with the same settings that worked in WinTest (use the same COM port and Baud rate).