Need help!!!

but the LCD does not display anything instead it displays "black pixels"...
adjust the voltage on the contrast input (see LCD datasheet).

Erik

adjust the voltage on the contrast input (see LCD datasheet).

Also ...

If you only get black pixels on the characters of the top one line, it can be an indication that the display has not been correctly initialised.

If that is the case, check the code.

Below is the code that i tried to program based on http://www.keil.com/appnotes/docs/apnt_161.asp

I do not know whether the way i initialise the Input/Output Ports correctly??

#include "C8051F200.h"
#include <stdio.h>
#include <intrins.h>

void Reset_Sources_Init()
{
    WDTCN     = 0xDE;
    WDTCN     = 0xAD;
}

void Port_IO_Init()
{
    // P0.0  -  Unassigned,  Open-Drain  Digital
    // P0.1  -  Unassigned,  Open-Drain  Digital
    // P0.2  -  Unassigned,  Open-Drain  Digital
    // P0.3  -  Unassigned,  Open-Drain  Digital
    // P0.4  -  Unassigned,  Open-Drain  Digital
    // P0.5  -  Unassigned,  Open-Drain  Digital
    // P0.6  -  Unassigned,  Open-Drain  Digital
    // P0.7  -  Unassigned,  Open-Drain  Digital

    // P1.0  -  Unassigned,  Open-Drain  Digital
    // P1.1  -  Unassigned,  Open-Drain  Digital
    // P1.2  -  Unassigned,  Open-Drain  Digital
    // P1.3  -  Unassigned,  Open-Drain  Digital
    // P1.4  -  Unassigned,  Open-Drain  Digital
    // P1.5  -  Unassigned,  Open-Drain  Digital
    // P1.6  -  Unassigned,  Open-Drain  Digital
    // P1.7  -  Unassigned,  Open-Drain  Digital

    // P2.0  -  Unassigned,  Push-Pull   Digital
    // P2.1  -  Unassigned,  Push-Pull   Digital
    // P2.2  -  Unassigned,  Push-Pull   Digital
    // P2.3  -  Unassigned,  Push-Pull   Digital
    // P2.4  -  Unassigned,  Push-Pull   Digital
    // P2.5  -  Unassigned,  Push-Pull   Digital
    // P2.6  -  Unassigned,  Push-Pull   Digital
    // P2.7  -  Unassigned,  Push-Pull   Digital

    PRT2CF    = 0xFF;
    PRT3CF    = 0xFF;
}

// Initialization function for device,
// Call Init_Device() from your main program
void Init_Device(void)
{
    Reset_Sources_Init();
    Port_IO_Init();
}

sbit RS = P2^5; // RS for P2.5
sbit RW = P2^6; // RW for P2.6
sbit E = P2^7; // E for P2.7

#define LINE1_ADDR 0x00 // Start of line 1 in the DD-Ram
#define LINE2_ADDR 0x40 // Start of line 2 in the DD-Ram


/* Display-Commands */

#define CLEAR_DISPLAY 0x01 // Clear entire display and set Display Data Address to 0
#define DD_RAM_PTR 0x80 // Address Display Data RAM pointer
#define DISP_INIT 0x38 // 8 bit 2 lines
#define INC_MODE 0x06 // Display Data RAM pointer incremented after write
#define LCD_ON 0x0C //Turn on LCD

/*
* ReadInstrReg: Read from Instruction Register of LCD Display Device
*/

static unsigned char ReadInstrReg (void)
{
        unsigned char Instr;
        P3 = 0xff; // DATA PORT is input
        RS = 0; // select instruction register
        RW = 1; // read operation
        E = 1; // give operation start signal
        _nop_ (); _nop_ (); // wait
        Instr = P0; // read Instruction
        E = 0;
        return(Instr);
}


/*
* WriteInstrReg: Write to Instruction Register of LCD Display Device
*/

static void WriteInstrReg (unsigned char Instr)
{
        RS = 0; // select instruction register
        RW = 0; // write operation
        E = 1; // give operation start signal
        _nop_ (); _nop_ (); // wait
        P3 = Instr; // write instruction
        E = 0;
        P3 = 0xff; // DATA_PORT is input [prevent I/O-Port from damage]
}


/*
* ReadDataReg: Read from Data Register of LCD Display Device
*/

static unsigned char ReadDataReg (void)
{
        unsigned char val;
        P3 = 0xff; // DATA_PORT is input
        RS = 1; // select data register
        RW = 1; // read-operation
        E = 1; // give operation start signal
        _nop_ (); _nop_ (); // wait
        val = P0; // read Instruction
        E = 0;
        return (val);
}


/*
 * WriteDataReg: Write to Data Register of LCD Display Device
 */

static void WriteDataReg (unsigned char val)
{
        RS = 1;          // select data register
        RW = 0;          // write operation
        E = 1;          // give operation start signal
        _nop_ (); _nop_ ();   // wait
        P3 = val;             // write value
        E = 0;
        P3 = 0xff;            // DATA_PORT is input [prevent I/O-Port from demage]
}

char putchar (char c)
{
          unsigned char line;
          if (c == '\n')
          {
            line = ReadInstrReg ();
            if (line & LINE2_ADDR)
                {       // is already in line 2
              WriteInstrReg (LINE1_ADDR | DD_RAM_PTR);   // place to start of line 1
                }
            else
                {
              WriteInstrReg (LINE2_ADDR | DD_RAM_PTR);   // place to start of line 2
            }
          }
          else
          {
                WriteDataReg (c);
          }
          return (c);
}

void wait(unsigned int time)
{
          int i;
            for (i = 0; i < time ;i++)
                {
                }
}

/*
 * Clear_Display: Write 0x20 to Display RAM
 */
static void Clear_Display (void)
{
          WriteInstrReg (CLEAR_DISPLAY);
          wait (1);
}

void main (void)
{
  unsigned char c;

  for (c = 'A'; c < 'H'; c++)
  {
    putchar (c);
  }
  printf ("Hello \n");

  Clear_Display ();
  for (c = 0; c < 10; c++)
  {
    printf ("This is Display Line %bd\n", c);
  }
  while (1);
}

/*void main (void)
{
        unsigned char c;
        for (c = 'A'; c < 'H'; c++)
        { // Put the characters A to H to the display
        putchar (c);
        }
        printf ("Hello \n"); // Puts ‘Hello’ to the display using printf()
        Clear_Display (); //Clear the display and reset cursor
        for (c = 0; c < 10; c++)
        {
        printf ("This is Display Line %bd\n", c); // another printf() testing
        }
        //while (1); //never stop
*/