Lcd_interfacing_unable to assign portd

[sx1]

Hello,

I am trying to interface the LCD with the PIC 16f877a microcontroller . I am using the MPLAB ICD2 debugger. But somehow I am never able to assign PORTD to 0x20 or 0x28 or any hexadecimal number starting with 0. I am using the 4 bit mode to interface the LCD. So to set the bit mode and number of lines I have to send 0x28 but i am unable to send it as the debugger interprets it is as 0x08. It works well for MPLAB SIM. I had burned the same code yesterday and was successful in printing the string but today somehow it isnt working and i am sure it isn't a hardware problem.

 

[john blue]

can you post your code?

 

[sx1]

#ifndef _XTAL_FREQ
// Unless specified elsewhere, 4MHz system frequency is assumed
#define _XTAL_FREQ 4000000
#endif

#include<htc.h>
#include<pic.h>
#include "delay.h"
#define D4 (1<<4) // the bit of portD connected to the particular pin of LCD is set to 1
#define D5 (1<<5)
#define D6 (1<<6)
#define D7 (1<<7)
#define LCD_RS RC4
#define LCD_RW RC3
#define LCD_EN RC5
#define UP (1<<4)
#define DOWN (1<<5)
#define LEFT (1<<6)
#define RIGHT (1<<7)
#define lcd_port PORTD
#define control PORTC
#define LCD_STROBE() ((LCD_EN = 1),(LCD_EN=0))

void lcdcmd (unsigned char cmd);
void lcd_reset();
void lcddata (unsigned char dat);
void lcd_clear(void);
void lcd_character(char c);
void lcd_line1(unsigned char pos);
void lcd_string(const char * s);

void lcdcmd (unsigned char cmd)
{
int i=0,sum=0,sum1=0;

__delay_us(40);

sum1=cmd+sum1;
for (i=0;i<=15;i++)
sum=sum+cmd;

lcd_port = ( sum1 & 0xF0 );
LCD_STROBE();
lcd_port=sum;
lcd_port = (lcd_port & 0xF0);
LCD_STROBE();
}

void lcd_reset()
{

TRISC=0;
TRISD=0;
PORTC=0x00;
__delay_ms(15); // wait 15mSec after power applied,
lcd_port = 0x03;
LCD_STROBE();
__delay_ms(5);
LCD_STROBE();
__delay_us(200);
LCD_STROBE();
__delay_us(200);
lcd_port = 2; // Four bit mode
LCD_STROBE();

}

void lcddata (unsigned char dat)
{
int i=0,sum=0;
__delay_us(40);

lcd_port=dat;
LCD_STROBE();

lcd_port = ( dat & 0xF0 );
LCD_STROBE();
lcd_port=dat;
for (i=0;i<=15;i++)
sum=sum+lcd_port;
lcd_port=sum;
lcd_port = (lcd_port & 0xF0);
LCD_STROBE();

}

void lcd_line2(unsigned char pos)
{
LCD_RS = 0;
lcdcmd(0xC0+pos);
}

void lcd_line1(unsigned char pos)
{
LCD_RS = 0;
lcdcmd(0x80+pos);
}

void lcd_string(const char * s)
{
LCD_RS = 1; // write characters
while(*s)
lcdcmd(*s++);
}

void lcd_clear(void)
{
LCD_RS = 0;
lcdcmd(0x01);
__delay_ms(2);
}

void lcd_character(char c)
{
LCD_RS = 1; // write characters
lcdcmd( c );
}


void lcd_init(void)
{
lcd_reset();
lcdcmd(0x28);
lcdcmd(0x0F); // Display on cursor on
lcd_clear();
lcdcmd(0x06); // Entry mode
// lcdcmd(0x08); //display off

lcd_line1(0);
lcd_string("Hi !!");
lcd_line2(0);
lcd_string("LCD Interfacing");
lcd_port=0x20;
// lcdcmd(0x01); // Clear display


}



void main(void)
{


TRISD=0x00;
TRISC=0x00;
lcd_init();

while(1);


}

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