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Need help!!!

Hi I am new in C language... I am doing a project that requires me to program 8051 to LCD in C language...So I am trying to display "HELLO WORLD" to the LCD in C language...I am using a C8051226 and a PIC0802-A 8X2 LCD...

I have gone online to search for sources on programming LCD...I have found a few sources in C and asm...Like www.8052.com/tutlcd.phtml and http://www.keil.com/appnotes/docs/apnt_161.asp...

I have tried to program myself based on http://www.keil.com/appnotes/docs/apnt_161.asp but the LCD does not display anything instead it displays "black pixels"...
I am also having problem configuring the ports...

I will be grateful if any of you guys can tell me how do i write these LCD data bus to the 8051 ports in C language??

DB0 EQU P3.0
DB1 EQU P3.1
DB2 EQU P3.2
DB3 EQU P3.3
DB4 EQU P3.4
DB5 EQU P3.5
DB6 EQU P3.6
DB7 EQU P3.7
DATA EQU P3

Parents

0 Fiddy Geeky over 18 years ago in reply to David Rose

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 â€˜Helloâ€™ 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
*/

Reply

0 Fiddy Geeky over 18 years ago in reply to David Rose

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 â€˜Helloâ€™ 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
*/

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