Help With My LCD Please!

I want to use a character lcd with my arduino uno. i'm new to Lcds. I used an lcd found in this link and its datasheet is also available in this link: www.robot-r-us.com/display-graphics/lcd16x2-with-led-backlight-parallel-interface.html?keyword=character+lcd

I followed the wirings in the arduino lcd tutorial: http://www.arduino.cc/en/Tutorial/LiquidCrystal

I've rechecked the wirings thrice already but only the backlights that turns on. I can't see the rectangles or characters.

i'm a little bit confuse because i usually see on the net with 16 pins but mine has only 14 but i just followed the labels on the pins. what could be the problem? pls help. I also notice that the back of the lcd seems to get a little hot.

it should have 3 + 3 + 8 + 2 pins, 16 in total, if it's 14, it might be missing the backlight. I had a 14 pin LCD once, the pinout was slightly different and it did not support 4 bit mode. Make sure yours support 4 bit mode before using the LiquidCrystal library.

Did you twiddle the potentiometer for the contrast adjustment?

Did you have a potentiometer?

I followed the wirings in the arduino lcd tutorial: http://www.arduino.cc/en/Tutorial/LiquidCrystal

Are you sure you didn't miss this part?

* LCD R/W pin to ground

You might want to try this tutorial: http://www.ladyada.net/learn/lcd/charlcd.html. Don't skip anything.

Don

If you do follow that ladyada tutorial, ignore the bit about connecting the backlight directly to +5 and ground - your lcd display (like both types I have used) needs a series resistor for the backlight.

floresta:

I followed the wirings in the arduino lcd tutorial: http://www.arduino.cc/en/Tutorial/LiquidCrystal

Are you sure you didn't miss this part?

* LCD R/W pin to ground

You might want to try this tutorial: http://www.ladyada.net/learn/lcd/charlcd.html. Don't skip anything.

Don

tnx. i still did not able to make my lcd work but i used another lcd and followed the tutorial. it was a breeze. Tnx much!

but i'm still wondering why my previos lcd didn't work? In it's datasheet it uses st7066u. is it compatible with the hd4470?

Not sure. But if you unplug the working lcd and plug in the non-working one, will the non-working one display something?

but i'm still wondering why my previos lcd didn't work? In it's datasheet it uses st7066u. is it compatible with the hd4470?

The ST7066u is compatible with the HD44780 so that is not your problem. Most likely you have an extended temperature range display. Many of those devices require a negative voltage on pin 3 instead of the slightly positive voltage that most displays require. Without this negative voltage the display will remain blank.

Don