Hi Sir's good day. I'm having a problem on configuring my 20x4 LCD. The LCD only shows block boxes on rows 1 and 3 (0,2 when configured in arduino) after I issued a command for it. Have tried re-wiring and using the example given in the Arduino IDE but no good. Felt like i'm stucked in this misery. Please help me =(
Hi,can you post a copy of your sketch and a copy of your circuit diagram, either CAD or picture of hand drawn circuit, in jpg, png or pdf.
This way we will be able to see what you are inquiring about and give accurate answers.
Tom...... 
Good day sir. Thanks for dropping by! Here are the Files sir just kindly extract em. These includes a Proteus Simulation File, my Sample code,and my pictures. Thanks sir!
PS: This is the circuit diagram i've been following in wiring the LCD sir:
LCD Files.rar (3.69 MB)
And one more thing sir. What is exactly the problem why I've been encountering this kind of LCD problem knowing that I have the right connections as well as the code. Thanks in advance for the reply sir!
Sir(s) good day. I have found out via experiment that my Arduino UNO 's several digital pins (which has been used during the experiment of LCD,12,11,5,4,3,2) doesn't show some enough voltage (around 0.2Vonly) when I use the above cited example program of LCD. However, when I enabled all of my uno's digital pins just for checking, it shows about 4.8V which then tells that my arduino uno is good. How come did this happen?
PS: Eager to wait for your sincere replies. ASAP
I had the same issue of black blocks showing,
I had to adjust the pot (contrast) until the the blocks were very faint or almost gone.
The line in code
lcd.begin(20,4);
should set the display to the 4 line mode,
so if you're only getting 2 rows that's troublesome,
and may be related to the pins showing 0.2 volts when driven high.
Seems to need pull up resistors (or turn on the internal ones?).
There are 2 more commands you might try
(after you get the pins at 0.2 V issue fixed):
** lcd.init();**
** lcd.backlight();**
P.S. Connect up the back light on pins 15 & 16,
if you don't get it working makes it into a nice night light