#define _XTAL_FREQ 8000000
#define RS RD2
#define EN RD3
#define D4 RD4
#define D5 RD5
#define D6 RD6
#define D7 RD7
#include <xc.h>
#include "lcd.h";
#include <pic16f877a.h>
// BEGIN CONFIG
#pragma config FOSC = HS
#pragma config WDTE = OFF
#pragma config PWRTE = OFF
#pragma config BOREN = ON
#pragma config LVP = OFF
#pragma config CPD = OFF
#pragma config WRT = OFF
#pragma config CP = OFF
//END CONFIG
int a;
void interrupt echo()
{
if(RBIF == 1) //Makes sure that it is PORTB On-Change Interrupt
{
RBIE = 0; //Disable On-Change Interrupt
if(RB4 == 1) //If ECHO is HIGH
TMR1ON = 1; //Start Timer
if(RB4 == 0) //If ECHO is LOW
{
TMR1ON = 0; //Stop Timer
a = (TMR1L | (TMR1H<<)/58.82; //Calculate Distance
}
}
RBIF = 0; //Clear PORTB On-Change Interrupt flag
RBIE = 1; //Enable PORTB On-Change Interrupt
}
void main()
{
TRISB = 0b00010000; //RB4 as Input PIN (ECHO)
TRISD = 0x00; // LCD Pins as Output
GIE = 1; //Global Interrupt Enable
RBIF = 0; //Clear PORTB On-Change Interrupt Flag
RBIE = 1; //Enable PORTB On-Change Interrupt
Lcd_Init();
Lcd_Set_Cursor(1,1);
Lcd_Write_String("Developed By");
Lcd_Set_Cursor(2,1);
Lcd_Write_String("electroSome");
__delay_ms(3000);
Lcd_Clear();
T1CON = 0x10; //Initialize Timer Module
while(1)
{
TMR1H = 0; //Sets the Initial Value of Timer
TMR1L = 0; //Sets the Initial Value of Timer
RB0 = 1; //TRIGGER HIGH
__delay_us(10); //10uS Delay
RB0 = 0; //TRIGGER LOW
__delay_ms(100); //Waiting for ECHO
a = a + 1; //Error Correction Constant
if(a>=2 && a<=400) //Check whether the result is valid or not
{
Lcd_Clear();
Lcd_Set_Cursor(1,1);
Lcd_Write_String("Distance = ");
Lcd_Set_Cursor(1,14);
Lcd_Write_Char(a%10 + 48);
a = a/10;
Lcd_Set_Cursor(1,13);
Lcd_Write_Char(a%10 + 48);
a = a/10;
Lcd_Set_Cursor(1,12);
Lcd_Write_Char(a%10 + 48);
Lcd_Set_Cursor(1,15);
Lcd_Write_String("cm");
}
else
{
Lcd_Clear();
Lcd_Set_Cursor(1,1);
Lcd_Write_String("Out of Range");
}
__delay_ms(400);
}
}
LCD.H
//LCD Functions Developed by electroSome
void Lcd_Port(char a)
{
if(a & 1)
D4 = 1;
else
D4 = 0;
if(a & 2)
D5 = 1;
else
D5 = 0;
if(a & 4)
D6 = 1;
else
D6 = 0;
if(a &
D7 = 1;
else
D7 = 0;
}
void Lcd_Cmd(char a)
{
RS = 0; // => RS = 0
Lcd_Port(a);
EN = 1; // => E = 1
__delay_ms(4);
EN = 0; // => E = 0
}
Lcd_Clear()
{
Lcd_Cmd(0);
Lcd_Cmd(1);
}
void Lcd_Set_Cursor(char a, char b)
{
char temp,z,y;
if(a == 1)
{
temp = 0x80 + b – 1;
z = temp>>4;
y = temp & 0x0F;
Lcd_Cmd(z);
Lcd_Cmd(y);
}
else if(a == 2)
{
temp = 0xC0 + b – 1;
z = temp>>4;
y = temp & 0x0F;
Lcd_Cmd(z);
Lcd_Cmd(y);
}
}
void Lcd_Init()
{
Lcd_Port(0x00);
__delay_ms(20);
Lcd_Cmd(0x03);
__delay_ms(5);
Lcd_Cmd(0x03);
__delay_ms(11);
Lcd_Cmd(0x03);
/////////////////////////////////////////////////////
Lcd_Cmd(0x02);
Lcd_Cmd(0x02);
Lcd_Cmd(0x08);
Lcd_Cmd(0x00);
Lcd_Cmd(0x0C);
Lcd_Cmd(0x00);
Lcd_Cmd(0x06);
}
void Lcd_Write_Char(char a)
{
char temp,y;
temp = a&0x0F;
y = a&0xF0;
RS = 1; // => RS = 1
Lcd_Port(y>>4); //Data transfer
EN = 1;
__delay_us(40);
EN = 0;
Lcd_Port(temp);
EN = 1;
__delay_us(40);
EN = 0;
}
void Lcd_Write_String(char *a)
{
int i;
for(i=0;a!='';i++)
Lcd_Write_Char(a);
}
void Lcd_Shift_Right()
{
Lcd_Cmd(0x01);
Lcd_Cmd(0x0C);
}
void Lcd_Shift_Left()
{
Lcd_Cmd(0x01);
Lcd_Cmd(0x08);
}