Help with parallel lcd


New member
I've wired a parallel lcd to my pc, and it didn't work. I found the solution: Pin 16 of the parallel cable wasn't connected. Now that the problem is fixed, the lcd does work but it shows the chars on wrong places: when i use cfah-wintest to show a b c d e f g h i j k l m n o p (without spaces inbetween), the screen shows e f g h a b c d m n o p i j k l (without spaces inbetween). Could it be that I screwed up the lcd by trying to initialize it with the 16th parallel cable pin not connected? (i read that that pin is used to show the lcd at which place to show the char). Could it be permanently damaged or is there a way to reverse this? Thanks alot (btw, the wiring is PERFECT and FOOLPROOF i checked it 100000 times, all wires correspond to the correct pin numbers and there aren't any bridged gaps).
Looking for additional LCD resources? Check out our LCD blog for the latest developments in LCD technology.

CF Tech

It sounds like you are really close. Most people take 100001 tries to get the wiring correct, so I think one more shot will get you there ;)

You probably have some of the data lines exchanged.

Use CFAH_WinTest to put only D0 high, and use your meter to make sure that only DO is high at the LCD. Then repeat for D1-D7.

What is the part number of the LCD?


New member
I guess i'll have to wait before being able to check my wiring again: since I read on various forums that it could have been a faulty lcd (which it isn't, because i did get it to work before :D ) i gave it to the shop and they sent it back to the manufacturer. As soon as it's back ( new one or the same, doesn't matter) ill be able to check the wiring again, although i'm absolutely sure that it is not an exchanged data cable. I don't know the part number because the lcd isn't here right now, but it is a 16x2 hd44780 with large characters and backlight. Thanks very much for the help, i hadn't tried testing that way with cfah_wintest before.