Adding the LCD (16X2 LCD DISPLAY) HD44780

///Adding the LCD (16X2 LCD DISPLAY) HD44780

Adding the LCD (16X2 LCD DISPLAY) HD44780


The LCD display in question is based on the very popular HD44780 controller. The Arduino platform has plenty of support for this controller and a library for its use is included with the Arduino IDE. The LCD will be driven in its 4-bit operation mode which requires the least pins. The 4-bit mode works by sending one nibble (4-bits) at a time to construct the entire byte. The display also has a character rom which simplifies use even further. If required custom characters can be programmed in but they are stored in volatile memory.

Success !

Using the Analogue Pins

Now that both the wireless module and LED driver IC are connected, digital pins available are running low. The LCD requires six ports on the microcontroller. Although many of the digital pins were taken the Arduino still had six free analogue ports. After a quick piece of research on the Arduino website it was discovered that the analogue pins can be addressed as digital pins by simply counting up six from pin 13, the last digital pin. This means pins 14 through 19 simply are digital representations of analogue pins 0 through 5. The display was connected and the library initialized to use the new pins, the LCD was working.

Wiring Diagram for Prototype:


Pin Name
1 Ground
2 5v Power
3 Contrast Voltage (10K Pot in our case)
4 R/S – Register Select (select between data or command register)
5 R/W – Read/Write (Select if reading or writing)
6 EN – Enable line
7-14 We are in 4-bit mode so we only use pins 11-14
15-16 Back-light power (In our case 5v LED BL)
By |2016-11-05T11:17:47+00:00December 22nd, 2010|Lightive Project|4 Comments

About the Author:

A PhD in Electronic Engineering. A love for photography ( An interest in tinkering, electronics and design. (


  1. Pavol March 23, 2012 at 7:47 am - Reply

    Hi Louis,
    very interesting project. I am new in hardware and I come along when searching for application using TRX433S transceiver. But I have problem to see the images in your blog. Do you have broken links here?
    Thanks for your reply in advance.

    • louis March 23, 2012 at 10:24 am - Reply

      Hey Pavol,
      It seems the images are down 🙁 Very sorry, have been so busy havent had time to maintain the blog.

      I’m off to university now but i will try to figure out whats wrong over the weekend.

      What are you planning to use the TRX433S for ? Perhaps i have some wiring diagrams i can send you in the mean time.

      Cheers, Louis

  2. Pavol March 26, 2012 at 7:34 am - Reply

    Hi Louis,

    originally i have read another article (Experiment – Connecting up and testing the RF12 / TRX433S modules) where the images were missed. We are going to use it for an home automation system based on xmega mcu and maybe using modbus protocoll.

    Results of your experiment were encouraging. It will be helpful if you can post me these images.

    Cheers, Pavol.

    • louis April 13, 2012 at 1:13 am - Reply

      Hey Pavol, I have sent you an email on the address you registered with. Hope it helps !



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