Displaying ASCII characters on NXN lcd is very easy. You just have to be familiar with the data types used to represent character or digit(INT integer, FLOAT, DOUBLE,CHAR , Long , unsigned or signed int float etc). You should know the number of bytes each data type takes and their equailent binary form.You should also know their conversions from one data type to other.
I think you all know that ASCII charaters take 8-bit memory, and if you dont know then remember ASCII characters and digits and all the special symbols , arthematic operators , roman digits and characters are all 8-bit wide.
From this point we can easily got a hint that its not very hard to display ascii values on 8x1 lcd or any other using micro controller because at a time we can send an 8-bit value to lcd using microcontroller.Hence ascii characters can easily be displayed using an lcd and a micro controller.    

HARDWARE REQUIREMENTS
16x2 lcd
ARDUNIO BOARD
CONNECTING WIRES
POTENTIOMETER (to set lcd contrast)
POWER source

NOTE:SOME CHARACTERS COULD NOT BE DISPLAYED.THIS IS BECAUSE THEY ARE THE SPECIAL SYMBOLS (LIKE SMILIES THAT ARE AT 0X00,0X01 TO 0X30 )THEY REQUIRE MORE BIG NXN MATRIX TO DISPLAY THEM.SOME BROKEN IMAGES ARE ALSO DISPLAYED THIS IS ALSO DUE TO THE SAME REASON MENTIONED ABOVE. 

                                               CODE
#include<LiquidCrystal.h>
LiquidCrystal lcd(13,12,11,10,9,8);

void setup()
{
lcd.begin(16 , 2);
lcd.clear();
}
void loop()
{
  int count=33;
  char ascii=0x00+33;
  while(count!=235)
  {
    lcd.setCursor(0, 0);
    lcd.print("DECIMAL = ");
    lcd.print(count);
    lcd.setCursor(0 , 1);
    lcd.print("ASCII = ");
    lcd.print(ascii);
    count++;
    ascii++;
    delay(1000);
    lcd.clear();
  }
}


Download the project .ino file from here

If you have any problem, leave a comment you will be helped out.