Parallax Serial LCD Arduino Subroutines

Parallax  Serial LCD 
2 rows x 16 characters Non-backlit (#27976) 
2 rows x 16 characters Backlit (#27977) 
4 rows x 20 characters Backlit (#27979) 

http://elmicro.com/files/parallax/seriallcd-v20.pdf

The best way to interface to this Serial LCD is to use the software serial library offered by Arduino environment. Be sure that the following is on your code.

///////////////////////// Libraries   ///////////////////////////////
  #include <SoftwareSerial.h>

////////////////////////     LCD Variables    ///////////////////////////
SoftwareSerial mySerial(10, 11); // RX, TX

Then, write subroutines to initialize the LCD.

void initializeLCD(){
  mySerial.begin(19200);   //change per LCD
  delay(500);
  // put your setup code here, to run once:
  mySerial.write(12);
  delay(5);
}

Subroutines to control the screen


void LCD_clearScreen(){
  mySerial.write(12);
  delay(10);
}

void Turn_backlight_on_LCD(){
  mySerial.write(17);
  delay(5);
}

void Turn_backlight_off_LCD(){
  mySerial.write(18);
  delay(5);
}

void Line_Feed_LCD(){
  mySerial.write(12);
  delay(5);
}

void Carriage_Return_LCD(){
  mySerial.write(13);
  delay(5);
}

void Move_Cursor(int line, int pos){
  switch (line){
    case 0:
        mySerial.write(128 + pos); 
        delay(5);
    break;
    case 1:
        mySerial.write(148 + pos); 
        delay(5);
    break;
    case 2:
        mySerial.write(168 + pos); 
        delay(5);
    break;
    case 3:
        mySerial.write(188 + pos); 
        delay(5);
    break;
    default:
    // do nothing
    break;
  }
 delay(5);
}


To write the a float value onto the LCD, it would work best if it was converted to a string as described below using dtostrf function

void LCD_floatValue(){
  int StringLen  = 7;
  int numVarAfterDec = 3;
  static char outstr[15];   // the array to store the results
  static float f_val = Lever_Position;

  dtostrf(Lever_Position,7, 1, outstr);
  

  Move_Cursor(0,0);
  delay(5);
  mySerial.print("Value ");
  mySerial.println (outstr);  
}