user55093: When I have tried interfacing my 16*2 LCD with Arduino I am getting only the black coloured boxes on my screen. What might be the problem?
Is there any solution to that? Do I need to connect any additional physical device to avoid that situation?  
product is here lcd display 16*2

user4143: There are two possible problems, and you haven't stated which it is.

A single row of blocks (just the top row)

This is caused by either bad communication (wrong wiring) or incorrect code. Basically, the display isn't being initialized properly by your code for whatever reason.

Two rows of blocks (the entire display full of blocks)

The display is being initialized properly, so both your code and wiring are correct.  However, the contrast setting of the display is wrong. You need to check the wiring for your contrast potentiometer and adjust as necessary.

55093: <p>When I have tried interfacing my 16*2 LCD with Arduino I am getting only the black coloured boxes on my screen. What might be the problem?</p>

<p>Is there any solution to that? Do I need to connect any additional physical device to avoid that situation?  </p>

<p><a href="http://uitechies.co.in/BBBcircuits/product.php?product=lcd-16x2-alphanumeric-display-jhd162a-8051-avr-arduino-pic-arm" rel="nofollow noreferrer">product is here lcd display 16*2</a></p>
 4143: <p>There are two possible problems, and you haven't stated which it is.</p>

<ol>
<li>A single row of blocks (just the top row)</li>
</ol>

<p>This is caused by either bad communication (wrong wiring) or incorrect code. Basically, the display isn't being initialized properly by your code for whatever reason.</p>

<ol start="2">
<li>Two rows of blocks (the entire display full of blocks)</li>
</ol>

<p>The display is being initialized properly, so both your code and wiring are correct.  However, the contrast setting of the display is wrong. You need to check the wiring for your contrast potentiometer and adjust as necessary.</p>
