LCD CODING IN EMBEDDED C

#define AT89C51
#undef PIC16F877A

#ifdef AT89C51
#undef PIC16F877A

sbit rs=P0^5;
sbit rw=P0^6;
sbit en=P0^7;

#define DATA P2

#else

#define rs RB1
#define rw RB2
#define en RB4
#define DATA PORTD

#endif

#define DELAY() delay(20)

void delay(unsigned int i)
{
while(i--);
}

void lcd_cmd(unsigned char c)
{
rs=0;
DATA=c;
en=1;
DELAY();
en=0;
}

void lcd_data(unsigned char d)
{
delay(500);
rs=1;
DATA=d;
en=1;
DELAY();
en=0;
}

void lcd_clr()
{
 lcd_cmd(0x01);
 delay(100);
 lcd_cmd(0x80);
}

void lcd_init()
{
  #ifdef PIC16F877A
    TRISB1=TRISB2=TRISB4=0;
    TRISD=0;
  #endif
    rw=0;
    lcd_cmd(0x38);
    lcd_cmd(0x0c);
lcd_clr();
}

void lcd_str(const unsigned char *str, const unsigned char pos)
{
 if(pos != 0xff) /*to follow previous written position*/
  lcd_cmd(pos);
 while(*str)
  lcd_data(*str++);
}