I have a problem with this display: PDF data sheet
I have connected it to an Arduino Nano using the LiquidCrystal Library in 4 bit mode. The pins are connected as in the reference: http://arduino.cc/en/Reference/LiquidCrystalConstructor
Everything works fine, but I have a problem with the contrast. First I have connected the LCD drive pin of the display directly to the ground. As result the display sometimes worked and sometimes the contrast was too low, which means the whole display turned white and you couldn't read the letters (look here for an image). I had to restart the Arduino many times until I could read something on the display. I have found here in this board the solution that I have to put a 10k POT between 5V and GND so that the LCD Drive pin gets around 0.5V. I works so I can set the contrast for perfect readability, but the problem is this only lasts till the next reset of the Arduino. So on every reset of the Arduino the voltage for the perfect contrast changes and I have to turn the POT. Is there any possibilty to ensure that the contrast is automatically set perfect, so that I can build the display in an case?
I have read something here that it perhaps works with different display librarys or other pin combinations from the Arduino to the display, but I don't know wether this is also valid for the latest library because that topic was last updated last year. Also I have read about putting the RW pin of the display also on GND. The contrast was fine then, but I got display errors: The line was filled with completely white fields on reseting the Arduino.