Arduino LCD via I2C (PCF8574AP)

Other Hardware Displays
1

Hi guys,,, I found the problem on HD44780 (16x2) display via I2C with a PCF8574AP.
when I uploaded the example sketch, there are a few problems. The first line is filled with black boxes.
I'm not able to print text on the display.

is there any solution ??

I use this code

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x38,16,2); // set the LCD address to 0x20 for a 16 chars and 2 line display

void setup()
{
lcd.init(); // initialize the lcd

// Print a message to the LCD.
lcd.backlight();
lcd.print("Hello, world!");
}

void loop()
{
}

I use this schematic

LCD I2C.JPG
LCD I2C.JPG430×571 30.8 KB

2

budiraharjo:
Hi guys,,, I found the problem on HD44780 (16x2) display via I2C with a PCF8574AP.
when I uploaded the example sketch, there are a few problems. The first line is filled with black boxes.
I'm not able to print text on the display.

is there any solution ??

...

Yes, there is a solution. Try looking over this thread for starters --> Converting 16x2 LCD to I2C (SOLVED) - Displays - Arduino Forum.

Also, delete your duplicate thread.

Don

3

do I need to add pull-up resistors on the i2c lines ?

4

do I need to add pull-up resistors on the i2c lines ?

That was spelled out pretty clearly in the thread that I recommended in my original reply, specifically in reply #8. Is there any part of what is said there about pull-ups that you don't understand?

Don