I'm trying to simply display some text on a 20x4 LCD display. I did same thing many times before; however, this LCD has a strange behavior. It always shows below pattern.
No difference if I connect or disconnect RS, RW, E and D4..7 lines. I tried different contrasts (using PWM). Power source is 5V and GND lines of Arduino UNO (which is connected to USB).
Once I wrote a code to do these repeatedly:
- clear screen
- delay 250ms
- print "Hello World"
- delay 1000ms
And while running this code, sometimes first character (0,0) blinked by the same time pattern.
Any idea? LCD malfunctioning? Breadboard is kinda old but still OK.
LCD controller is hd44780 (as seller website said).