4-bit LCD problem while interfacing, program fluctuation

#ifndef __LCD_H__
#define __LCD_H__

typedef unsigned char bit_8;


/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LCD Port Configuration
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

sbit rs=P2^0; //lcd pin (4)

sbit en=P2^2; //lcd pin (6)

bit status=0;
sbit lcd_on=P3^7;

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LCD Command MACROS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

#define lcd_delay 400
#define LCD P2

#define LCD_CLEAR 0x1
#define RETURN_HOME 0x2
#define DEC_CURSOR 0x4
#define INC_CURSOR 0x6
#define DISP_OFF_CUR_OFF 0x8
#define DISP_OFF_CUR_ON 0xA
#define DISP_ON_CUR_OFF 0xC
#define DISP_ON_CUR_BLINK 0xE
#define SHIFT_CUR_LEFT 0x10
#define SHIFT_CUR_RIGHT 0x14
#define SHIFT_DISP_LEFT 0x18
#define SHIFT_DISP_RIGHT 0x1C

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Function Prototypes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
void lcd_init_write(unsigned char);
void lcd_ini(void); // Initialize LCD
void lcd_busy(void); // Check Busy
void lcd_com(bit_8); // Sending Command
void lcd_data(bit_8); // Sending single character
void string(unsigned char item[],unsigned char); // Sending String
void wrt_value(bit_8); // Sending 8-bit Decimal value
void cursor(bit_8,bit_8); // Bringing Cursor to (X,Y) location X -> (1,2) and Y -> (1-16)
void delay(unsigned int);
void buzz(unsigned char);
void delay_(unsigned int time);






/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LCD Initialization
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

void lcd_ini(void)
{ unsigned char i;
for(i=0;i<3;i++)
{delay(lcd_delay);
lcd_init_write(0x30);
}

lcd_init_write(0x20); // 0x20 for 4-bit
delay(lcd_delay);
lcd_com(0x28); //Display Off, Cursor Off, Blink Off
delay(lcd_delay);
lcd_com(4); // Clear Screen & Returns the Cursor Home
delay(lcd_delay);
lcd_com(0x85);
delay(lcd_delay);
lcd_com(6); //Inc cursor to the right when writing and don’t shift screen
delay(lcd_delay);
lcd_com(1);
delay(lcd_delay);
}

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
waiting for LCD to execute
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/


/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Writing command to LCD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

void lcd_com(unsigned char a)
{
unsigned char temp;
if(status)
{
status=0;
goto next;
}
rs=0;
next:

temp=a;
temp&=0xf0; // Mask Lower 4 Bits
LCD&=0x0f; // Make No Affect on 0ther Port Pins
LCD|=temp; // Send Higher Nibble to LCDPORT
en=1;
delay(lcd_delay); //Send Enable Signal to LCD
en=0;
temp=a<<4; //Left Shift Byte Four Times
temp&=0xf0; // Mask Higher 4 Bits
LCD&=0x0f; // Make No Affect on 0ther Port Pins
LCD|=temp; // Send Lower Nibble to LCDPORT
en=1;
delay(lcd_delay); // Send Enable Signal to LCD
en=0;




}

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Writing string to LCD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/


void string(unsigned char item[16],unsigned char line)
{
unsigned char fac,i,j,cmd;
for(i=0;item!='\0';i++);
if(i<=16)
{
fac=(16-i)/2;
if(line==1)
cmd=128;
else if(line==2)
cmd=192;
lcd_com(1);
lcd_com(cmd+fac);
for(j=0;item[j]!='\0';j++)
{
lcd_data(item[j]);
delay(5);
}
}

else
{
lcd_com(1);
lcd_on=1;
buzz(2);
}
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Writing data to LCD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

void lcd_data(unsigned char a)
{
status=1;
rs=1;
lcd_com(a);
}

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Writing 8-bit Value to LCD
e.g. writing 63 on LCD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

void wrt_value(bit_8 x)
{
bit_8 temp;
temp = x/0x10;
if(temp>9)
return;
else
lcd_data(temp+0x30);
temp = x%0x10;
if(temp>9)
return;
else
lcd_data(temp+0x30);
}

/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Bringing Cursor to (X,Y) location of LCD
X -> 1,2
Y -> 1,16
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

void cursor(bit_8 x, bit_8 y)
{
if((x<1||x>2)&&(y<1||y>16))
{
x=1;
y=1;
}
if(x == 1)
lcd_com(0x7F+y);
else
lcd_com(0xBF+y);
}

/* -------------------------------------------------------------*/


void lcd_init_write(unsigned char a)
{
rs=0;
LCD=a;
en=1;
delay(lcd_delay);
en=0;
}


#endif

Click to expand...