[PIC] HC-SR04 ultrasonic sensor problem.

#include <p18f4580.h>
#include <delays.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#pragma config OSC= HS
#pragma config WDT=OFF
#pragma config LVP=OFF

#define Trig PORTBbits.RB3
#define Echo PORTBbits.RB2

void T0Delay10us(void);
void T0Delay5ms(void);
void uart(void);
void Call_Init_PIC (void);
void sendPulse(void);

unsigned int distance ;
unsigned int time;
unsigned f,b;

void main(void)
{
TRISDbits.TRISD2=0;
TRISDbits.TRISD3=0;
TRISDbits.TRISD1=0;
TRISDbits.TRISD0=0;
Call_Init_PIC ();
uart();
while(1)
{
TMR1H= 0;
TMR1L= 0;
sendPulse();

while(Echo == 0);

T1CONbits.TMR1ON = 1;
while(Echo == 1);
T1CONbits.TMR1ON = 0;  

Delay10KTCYx(255);
Delay10KTCYx(255);
Delay10KTCYx(255);
Delay10KTCYx(255);                   

time= TMR1H;
time= time<<8;
time= time|TMR1L;
//time = (TMR1L + (TMR1H<<8));

distance = time/28.8;
f=distance/10;
b=distance%10;
printf("\r\nDistance = %d.%d cm",f,b);  
PIR1bits.TMR1IF=0;
Delay10KTCYx(255); 
T0Delay5ms(); 
/*
if(distance>=0 && distance<=250)
{
PORTDbits.RD2=1;
//printf("\ndangerous");
}

if(distance>=251 && distance<=500)
{
PORTDbits.RD3=1; 
}

if (distance>=501 && distance<=1000)
{
PORTDbits.RD0=1; 
}

if(distance>=1001)
{
PORTDbits.RD1=1;
//printf("\nsafe zone");
}
*/
}
}

void Call_Init_PIC (void)
{
TRISBbits.TRISB3=0;
TRISBbits.TRISB2=1;
}


void uart(void)
{
TXSTA=0B00100000;
SPBRG=32;
TRISCbits.RC6=0;
RCSTAbits.SPEN=1;
}


void sendPulse(void)
	{
	Trig=1;
	T0Delay10us();
	Trig=0;
	}


void T0Delay10us()
	{
	T0CON=0x08;
	TMR0H=0XFF;
	TMR0L=0XCE;
	T0CONbits.TMR0ON=1;
	while(INTCONbits.TMR0IF==0);
	T0CONbits.TMR0ON=0;
	INTCONbits.TMR0IF=0;
	}


void T0Delay5ms()
	{
	T0CON=0x08;
	TMR0H=0X9E;
	TMR0L=0X58;
	T0CONbits.TMR0ON=1;
	while(INTCONbits.TMR0IF==0);
	T0CONbits.TMR0ON=0;
	INTCONbits.TMR0IF=0;
	}

unsigned long Over;
Unsigned long time;
....


while(1)
{

sendPulse();
T1CONbits.TMR1ON = 0;  
PIR1bits.TMR1IF=0;
TMR1H= 0;
TMR1L= 0;
Over=0;
time=0;

while(Echo == 0);
T1CONbits.TMR1ON = 1;
while(Echo == 1)
{
 if (PIR1bits.TMR1IF==1)
  {
     Over=Over+65536;
     PIR1bits.TMR1IF=0;
  }
}
T1CONbits.TMR1ON = 0;  

time= TMR1H;
time= time<<8;
time= time|TMR1L;
Distance= (time + Over)/58;    // <- don't forget travel of sound in both way forward then reverse

// or you can  use floating point calculus  to get distance in mm  distance/5.88

unsigned long Over;
Unsigned int  time;
float Distance;


while(1)
{

sendPulse();
T1CONbits.TMR1ON = 0;  
PIR1bits.TMR1IF=0;
TMR1H= 0;
TMR1L= 0;
Over=0;
time=0;

while(Echo == 0);
T1CONbits.TMR1ON = 1;
while(Echo == 1)
{
 if (PIR1bits.TMR1IF==1)
  {
     Over=Over+65536;
     PIR1bits.TMR1IF=0;
  }
}
T1CONbits.TMR1ON = 0;  
time= TMR1H;
time= time<<8;
time= time|TMR1L;
printf("\r\nTime = %d",time);
printf("\r\nOver = %ul",Over); 
Distance=(float) time + (float) Over;
printf("\r\nTravel duration %4.1f µS",Distance); 
Distance=Distance*0.2/5.88;    // counts * 0,2µS / 5.88 => result in mm
printf("\r\nDistance %4.1f mm",Distance);