I've hooked up my Arduino on this LCD, and after running the following code, all I see is a row with black boxes and another one empty.

//LiquidCrystal d(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(0, 1, 2, 3, 4, 5);

void setup() {                
     lcd.begin(16, 2);
     lcd.print("hello, world!");

void loop() {
     lcd.print("hello, world!");       

Wiring: table showing wiring between arduino and lcd

(The UTP cable is used just for the data lines :-)

Actual wiring photos: (sorry for the total klutz in the wiring, I had limited solid-core wires so I had to use these scrap ones)

wiring wiring wiring

  • CAT 5 solid core is notorious for making poor connection in a breadboard. Have you tried a continuity check between the output pin of the MCU and the LCD input pin for each? That is, checking it without touching the wire in question.
    – Samuel
    Jun 9, 2014 at 0:24
  • I think your contrast resistor may be too high. Do you have a 10k pot so you can adjust it? Do you also have a schematic that you're following? Can you post this up
    – Kinnectus
    Jun 9, 2014 at 9:12
  • I'l try connecting with non-CAT5e wires and report back Jun 9, 2014 at 12:53
  • @Samuel I just tried with normal solid-core wires and still nothing, so I believe wire problems are ruled out. Jun 9, 2014 at 13:11
  • @BigChris I'm afraid i don't actually have breadboard space for a potentiometer ): Jun 9, 2014 at 13:12

1 Answer 1


The problem was that the R/W pin on the LCD was left floating, after I connected it to GND, I started working :)

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