I have recently acquired an Arduino and LCD display, I have been experimenting with it and I have made it work, and had it working for a few days on a few different sketches. This morning, I uploaded a new sketch to the unit and all of a sudden it comes up with a line of solid blocks on the top row on the LCD (Freetronics 16×2). This happens even if I upload a new blank sketch, it stays with the top row of solid blocks.
Arduino LCD crashing / solid top line
arduinolcd
Best Answer
A top line of solid blocks appears when the display has not been initialized, or if it has become deinitialized after a brownout. Be sure that the code initializes the display properly and that the decoupling capacitor is functional.