LCDInfo.com

Hello there!

We have a 64128A-LCD and wrote a Linux-program to show some mp3Player functions on this display...

The program works very fine and also the LCD shows anything we want. But only on notebooks! We tried the program and the LCD on 3 totally different notebooks and it works...

But then we tried it all on 3 different desktop PCs. The program works, but the LCD shows just pieces of the correct "pictures" and texts. There also are black beams and stripes on the display, so that we can't really see anything we want.

We tried nearly everything to remedy the problem, it doesn't work...

The only difference we noticed was, that the data pins of the parallel port have 3.4V at the notebooks and 5.1V at the desktop PCs!

Could that be the problem?

Thanks in advance for your help!!

I've seen the effects you described when the timing to drive to display is bad. And of course voltage levels effect the timing. I don't know why it exactly behaves like this though. Have you tried different parallel port settings in BIOS ? If that doesn't help then pull up resistors in the data lines might be worth trying.