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Help needed - interface with LCD

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ken ric

New Member
Heya all,

I'm new to this forum and i stumbled upon it while searching for help on Google about LCD screens.

The LCD screen i'm mentioning is not those LCD monitors, it is those smaller electronic screens, which i think most of the forum members here would be familiar with :)

The LCD screen i'm using for my project is a 2x16 display(16 pins) and i'm using an Atmel 8952 microcontroller to interface it with a 4x4 keypad. the problem is, after i burn a test program into the 8952 to test the LCD, there is not a single display on it. I think i had setup the LCD connections correctly into the controller, but still there is no display at all. I'm using 5V to power the controller and also the LCD. The test program i used is from a book and i dont think the program could be faulty. Also, before i connect the LCD to the controller, i did some test on the controller to see if it has any problem and it turns out fine.

Is this because of the LCD screen is faulty? Are there any ways to test the LCD screens without using a controller?

lastly, please bear with me, i'm new to electronics and i'm an eager learner, but i know my electronic 'terms' used sounds very noob, so please correct me if i'm wrong, thanks alot!! :D
 

crust

Member
If your LCD uses the HD44780 controller (which it probably does if you are able to use some code from a book), then you can test it with the parallel port of your PC. There is a description about how to do this here.

but yet, it is possible your display is faulty or damaged.

good luck.
 

Exo

Active Member
ken ric said:
Heya all,
Is this because of the LCD screen is faulty? Are there any ways to test the LCD screens without using a controller?
If the display has a HD44780 controller then you can test it by applying power to it while leaving the data pins unconnected. The top line should turn all pixels on as a self-test

Are you getting anything at all ? if not, did you connect the contrast pin ? (pin 3).
 

panic mode

Well-Known Member
I had same problem. Culprit was potentiometer for contrast (wipper didn't make contact). All displays I've used so far use either 14 or 16 contacts (first 14 were same on my displays).
Pin1 is GND
Pin2 is +5V
Pin3 is contrast (0-5V on most models) etc.
These three pins should be enough to power up display and when contrast is changed you should see blocks on display (one for each character).

Btw. some displays do require negative voltage as well. ;-(
 
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