Controlling an Lcd Display (HD44780) via I2C Bus

Posted on 23/07/2013 by c00kiemon5ter Δημοσιεύτηκε στο Arduino Tutorials — 6 Σχόλια ↓

Required Hardware

Controlling an Lcd Display (HD44780) via I2C Bus. Learn in this tutorial how to connect your Lcd Display with Arduino using only 2 pins, to make this you will need an PCF8574A Expander. The PCF8574 extender is available in two versions, the PCF8574 and the PCF8574A. The only difference between the two is the I2C base address. The base address for the PCF8574 is 0x20 and the base address for the PCF8574A is 0x38.

Wiring

To wire your LCD screen to your Arduino via PCF8574A, connect the following pins:

Lcd Pin 1 (Vss) –> Arduino Ground
Lcd Pin 2 (Vdd) –> Arduino +5V
Lcd Pin 3 (Vo) –> Middle Pin of Potentiometer 10K
Lcd Pin 4 (Rs) –> Pcf8574 Pin 11
Lcd Pin 5 (Rw) –> Pcf8574 Pin 10
Lcd Pin 6 (E) –> Pcf8574 Pin 9
Lcd Pin 7-10 –> N/C
Lcd Pin 11 (D4) –> Pcf8574 Pin 4
Lcd Pin 12 (D5) –> Pcf8574 Pin 5
Lcd Pin 13 (D6) –> Pcf8574 Pin 6
Lcd Pin 14 (D7) –> Pcf8574 Pin 7
Lcd Pin 15 (A) –> Arduino +3.3V
Lcd Pin 16 (K) –> Arduino Ground
Don’t forget to connect and the other 2 pins of potentiometer to Ground and +5V.

To wire your PCF8574A Expander to your Arduino, connect the following pins:

Pin 1 (A0) –> Arduino Ground
Pin 2 (A1) –> Arduino Ground
Pin 3 (A2) –> Arduino Ground
Pin 4 (P0) –> Lcd Pin 11
Pin 5 (P1) –> Lcd Pin 12
Pin 6 (P2) –> Lcd Pin 13
Pin 7 (P3) –> Lcd Pin 14
Pin 8 (Vss) –> Arduino Ground
Pin 9 (P4) –> Lcd Pin 6
Pin 10 (P5) –> Lcd Pin 5
Pin 11 (P6) –> Lcd Pin 4
Pin 12-13 –> N/C
Pin 14 (Scl) –> Arduino Pin A5
Pin 15 (Sda) –> Arduino Pin A4
Pin 16 (Vdd) –> Arduino +5V

Recommended Software

none

Instructions and Code

Με ετικέτα: 16x2, arduino, display, HD44780, lcd, pcf8574A, screen

6 comments on “Controlling an Lcd Display (HD44780) via I2C Bus”

orestis says:

31/12/2013 at 12:35 am

Hey,I have a problem with that.I have an LCD display with a LCM1602 IIC V1 on it but when i upload the code( any code) I can adjust the contrast but the only thing I get is ( only in one line) these little squers.Please help.
What is wrong?

Reply
- Stav says:
  
  31/12/2013 at 6:24 pm
  
  Use this library, it worked ok for me.
  
  https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads
  
  Reply

apollonios says:

21/02/2014 at 2:59 pm

I got an error when I try to compile this example:

lcd_I2C_example.cpp.o: In function `__static_initialization_and_destruction_0':
d:\Downloads\arduino-1.5.2-windows\arduino-1.5.2/lcd_I2C_example.ino:4: undefined reference to `LiquidCrystal_I2C::LiquidCrystal_I2C(unsigned char, unsigned char, unsigned char)'
lcd_I2C_example.cpp.o: In function `setup':
d:\Downloads\arduino-1.5.2-windows\arduino-1.5.2/lcd_I2C_example.ino:8: undefined reference to `LiquidCrystal_I2C::init()'
d:\Downloads\arduino-1.5.2-windows\arduino-1.5.2/lcd_I2C_example.ino:10: undefined reference to `LiquidCrystal_I2C::backlight()'

I use LiquidCrystal_I2C.h 3.246 bytes and another 8.233 bytes, with the same results (this error)
can anybody help me?

thanks
ing Prodromos Sabaidis, Thessaloniki, Greece

Athanasios Loi says:

25/02/2014 at 6:48 pm

I tried with this library: http://learning.grobotronics.com/download/arduino-libraries/LiquidCrystal_I2C_Library.zip
on Arduino IDE version 1.5.5 and it worked fine.

Reply
apollonios says:

03/03/2014 at 8:43 am

now it compiles (I got help from a friend, atmega@xs4all.nl, I had to put all files of .zip under /libraries/)
but does not work , displays nothing!
I have checked the wiring, it looks ok.

Makis

Reply
thanasisloi7 says:

03/03/2014 at 4:17 pm

Be sure that you use expander PCF8574A else if you are using another version of PCF for example 8574T you must change the address to 0x20.
Also check the contrast from your trimmer!

Reply