20x4 Serial LCD. Won't print 20 chars, only 16 per line

Development Boards MicroMod
1

Somehow it only prints 16 chars per line. Dunno why?

http://img8.imageshack.us/img8/6742/s6300886j.jpg

Code:

#include <NewSoftSerial.h>
NewSoftSerial mySerial(7, 8);

void setup() 
{
  mySerial.begin(9600);
}

void loop() {
  // Example usage:
  clearLCD();
  backlightOn();
  //Print text on each line
  selectLineOne();
  delay(100);
  mySerial.print("AAAAAAAAAAAAAAAAAAAA");
  delay(10000);

}
//SerialLCD Functions
void selectLineOne(){  //puts the cursor at line 0 char 0.
  mySerial.print(0xFE, BYTE);   //command flag
  mySerial.print(128, BYTE);    //position
}
void selectLineTwo(){  //puts the cursor at line 2 char 0.
  mySerial.print(0xFE, BYTE);   //command flag
  mySerial.print(192, BYTE);    //position
}
void selectLineThree(){  //puts the cursor at line 3 char 0.
  mySerial.print(0xFE, BYTE);   //command flag
  mySerial.print(148, BYTE);    //position
}
void selectLineFour(){  //puts the cursor at line 4 char 0.
  mySerial.print(0xFE, BYTE);   //command flag
  mySerial.print(212, BYTE);    //position
}

void clearLCD(){
  mySerial.print(0xFE, BYTE);   //command flag
  mySerial.print(0x01, BYTE);   //clear command.
}
void backlightOn(){  //turns on the backlight
  mySerial.print(0x7C, BYTE);   //command flag for backlight stuff
  mySerial.print(157, BYTE);    //light level.
}
void backlightOff(){  //turns off the backlight
  mySerial.print(0x7C, BYTE);   //command flag for backlight stuff
  mySerial.print(128, BYTE);     //light level for off.
}
void backlight50(){  //sets the backlight at 50% brightness
  mySerial.print(0x7C, BYTE);   //command flag for backlight stuff
  mySerial.print(143, BYTE);     //light level for off.
}
void serCommand(){   //a general function to call the command flag for issuing all other commands   
  mySerial.print(0xFE, BYTE);
}

And! how come this 20x4 needs some delay? Or else it won’t show anything. The 16x2 lcd I got just prints it without the need for a delay.

2

Take a look at NewSoftSerial.h and the print function. I think it only looks at the first 16 chars.

You can edit the utility to go through all 20.

3

NewSoftSerial is a serial library and, unless it was written specially for your Serial LCD, it should have nothing to do with your problem. Look at the documentation for the serial LCD. Maybe it is powering up in 16 x n mode and can be configured by sending the appropriate command sequence to it.

As far as the delay goes, some LCDs process commands faster than others. Generally, anything the clears the screen or does cursor positioning should be given at least 50 ms to complete, just to be safe. Check the docs for the LCD for the specifics.