Lcd display only show white boxes

[kiketobr]

i am using a arduino uno connected to my laptop
trying to display '' Hello World '' but these white boxes keep showing up
i alredy tried to change the contrast with a potentiometer

Please somebody help me!!

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2);

int backLight = 13;
void setup(){
  pinMode(backLight, OUTPUT);
  digitalWrite(backLight, HIGH);

  lcd.begin(16, 2);  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Hello World");

  lcd.setCursor(0, 1);
  lcd.print("Hello World");
  Serial.begin(9600);
}
void loop(){
  delay(1000);
  lcd.noDisplay();
  delay(1000);
  lcd.display();
}

[jremington]

Thanks for posting code correctly in your first post!

The white boxes are a sign that power is applied, and the display is "live", but no communications have been received to initialize the display.

Double check all your wiring, and especially, the pin assignments in the LiquidCrystal instantiation.