in my case, the LCD has blue backlight .
So BLACK bar means the bar darker than the backlight OR brighter than backlight?

should appear white right?
Added on January 8, 2011, 3:03 pmI googled around and found this:
QUOTE
Quote:
I then tried using the LCD4Bit library and example sketch, but all i get are 2 lines of black squares on the 1st & 3rd line, and the compiler didn't show any problem before upload.
When you get the two lines of black squares it means that you have the power applied and the contrast set properly but the LCD controller has not been initialized properly.
Many of the libraries that are available do not follow the datasheet recommendations to use software initialization or they do not implement that initialization properly.
I suggest you try the latest official LiquidCrystal library (Arduino v0017) and try the accompanying example programs. This library follows the datasheet more closely than all the others and should work for you.
Don
From:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.p...=1251279124/6#6QUOTE
When you say it goes to full bars, do you mean ?
I had an issues where i got the lines of black squared on lines 1 & 3 of the LCD which meant it wasn't initializing the screen. which i suspect is the same for you.
Make sure you have the lcd initialized with the following code, and just make sure the pins defined match the input/output pins you are using ?
Quote:
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
It seems this LCD is a bit different. Looks like I have to program the LCD to initialize it properly.
I think I wanna buy 2x20 module that u're using perhaps can work out of the box. Not so ready to do some programming though

Another issue here :
http://translate.google.com/translate?js=n...php%3Ft%3D28415Looks like it's not the contrast problem. I have tried to arjust with the pot, no change.
This post has been edited by jeopardise: Jan 8 2011, 03:12 PM