Trying to send something on this display (Powertip PC2004A 20x4) but have no luck. All I have is squares in 1. and 3. line. Depending on the sketch I can manage to make it blink (those squares) but other things are not possible.
I assume that problem can come from:
1)Wrong initialization of this type of LCD which is based on ST7066U instead on mostly common Hitachi LCDs. On Internet a lot of people talking about problems with initialization of ST7066U because of different timing intervals (delays) and many other differences. Is there anybody that has working sketch for ST7066U? Does Liquid Crystal library has support for this type of displays.
2) Programming - For testing purposes I was using Liquid Crystal library (Arduino 1.05) (Display.ino) and wondering if I have completed wiring and "reconfiguration" of code as I should. Wiring is done as it is written in ino file. lcd variable is initialized as wired. Now, if I have LCD 20x4, should I use:
lcd.begin(16, 2); or lcd.begin(20, 4);
... asking because as far as I see all are using lcd.begin(16, 2) regardless of number of columns and rows !?? So If I need to address (print on) second line 4. place - it is actually first line place 24. Is it ?
3) Wiring display - if I have 4-bit scenario, do I have to connect to GND all LCD's pins not used ? For example, If I don't use pins DB0-DB3 should I connect them to GND? Same question about back-light - this model I have is without back-light, so, should I connect pins 15 and 16. to GND or leave it as it is?