Can't display serial data

Hi All,

i’ve written a program in delphi that sends a string to the COM port, the arduino reads it and sends it
back. I can read the send back data perfectly. What i don’t seem to manage is how i can convert
the serial data (they come in trough decimal numbers that represent the ASCII table) and show it
on my lcd. Whatever i try, not works and it keeps outputting me the decimals instead of the string
Serial speed is both tested on 9600 and 19200 , works the same way to read/write

#include <LiquidCrystal.h>
LiquidCrystal lcd(8, 9, 4,5,6,7); 

int val = 0;       // variable to store the data from the serial port
int ledPin1 = 13;   // LED connected to digital pin 13
int state = 0;
String content = "";
String character;

void setup() {

  pinMode(ledPin1,OUTPUT);    // declare the LED's pin as output
  Serial.begin(19200);        // connect to the serial port

void loop () {
  val =;      // read the serial port
  if (val > 0) {
  lcd.setCursor(0, 1);

I thought this was an easy task to get out but i’m kinda stuck in this. Any ideas ?

Maybe it's just me but I sometimes get funny behaviour when I exceed 9600 for the serial.

I'm not sure what this: character=String(val);

is intended to do. Are you trying to build a string out of incoming chars in: content.concat(character);

but your characters are incoming in val. Why not just use: content.concat(val);

Strings are terminated with a null character. I'm not sure what converting each char to a string is doing, either.


I'm very new to this myself, but when my LCD was working, I couldn't pass strings to it. It's likely that I was missing something in my code, but, regardless, I think arloG is on to something with bypass the string typing.

Sorry I took so long. To test this, I had to retrieve an LCD from my pile of components and solder leads to it.

I tried to simplify what you had and then test it with the Arduino IDE serial monitor. I assumed that you want to send strings terminated with a null and have these strings displayed starting at the first position on the top row of the LCD. You had lcd.setCursor(0, 1); which I think is the second row.

Since I was using the Arduino serial monitor, I didn’t know how to generate a null so I chose “X” as the terminating character. When this program reads an “X”, it clears the display and will then start displaying again at first char/top row. Remove these lines if delphi is doing the sending. Otherwise, “X” will cause a mysterious display reset.

There are some other changes. I think you need to set up the LCD in, er, setup. I threw out the led and other stuff that wasn’t required for this snippet. And I have a compulsion to dither other people’s code.

#include <LiquidCrystal.h>
LiquidCrystal lcd(8, 9, 4,5,6,7); 

char val = 0;            // variable to store the data from the serial port

void setup() 
{   lcd.begin(16,2);               //need to set up LCD characteristics
    Serial.begin(9600);          //19200 doesn't work for me

void loop () 
{   if (Serial.available())        //look for serial data 
    {   val =;       // if it's available, read the serial port
        if (val == 0)                   //I assume that you're using null as the terminator of the Delphi string
        else if(val=='X')              //for debugging from serial monitor
        {   Serial.write(val);     //echo char to serial monitor
            lcd.print(val);         //print char on LCD