unsigned long t;
short flag = 0;
char txt[10];

void interrupt(void) {
if(flag == 0) {          //if rising edge detected
  CCP1CON = 0x04;  //wait for falling edge
  TMR1L = 0;            //clear TMR1L & TMR1H
  TMR1H = 0;
  PIR1.B2 = 0;
  flag = 1;
  }
else if(flag == 1) {    //if falling edge detected
  CCP1CON = 0x05;   //wait for rising edge
  t = TMR1H;            //read TMR1L & TMR1H
  t = t << 8;
  t = t | TMR1L;
  PIR1.B2 = 0;
  flag = 0;
  }
}

void main() {
UART1_Init(9600);
Delay_ms(100);
T1CON = 0x01;
CCP1CON = 0x05;
INTCON = 0xC0;
PIE1 = 0x04;
TRISB3_bit = 1;

while(1) {
  LongToStr(t, txt);
  UART1_Write_Text(txt);
  UART1_Write(10);
  UART1_Write(13);
  delay_ms(50);
  }
}

unsigned long t1rise, t1fall, result = 0;
char txt[10];
short s1flag;

void Interrupt(){
  if (TMR0IF_bit){
    TMR0IF_bit = 0;
    TMR0 = 255;
    if(RB4_bit && !s1flag){       //
     t1rise = TMR1H;
     t1rise = t1rise << 8;
     t1rise = t1rise | TMR1L;
     s1flag = 1;
     }
     if(!RB4_bit && s1flag){      //
      t1fall = TMR1H;
      t1fall = t1fall << 8;
      t1fall = t1fall | TMR1L;
      result = t1fall - t1rise;
      LongToStr(result, txt);
      UART1_Write_Text(txt);
      UART1_Write(13);
      s1flag = 0;
    }
  }
  if (TMR1IF_bit){
    TMR1IF_bit = 0;
    TMR1H = 0x00;
    TMR1L = 0x00;
  }
}

void main() {
  TRISB4_bit = 1;
  OPTION_REG = 0b10001000; //Bits 0:2 prescaller rate select
  INTCON = 0b11100000;
  T1CON = 0x01;
  TMR1IE_bit = 1;
  UART1_Init(9600);
  while(1);
}

#define TX_BUF_SIZE     (8)
#define T1_RISE             (0)
#define T1_FALL             (1)

unsigned short tx_buf[TX_BUF_SIZE][2];
volatile unsigned char tx_buf_head;
volatile unsigned char tx_buf_tail;

volatile unsigned char s1flag;



void Interrupt(){

  unsigned short t1val;

  if (TMR0IF_bit){
    TMR0IF_bit = 0;
    TMR0 = 255;
    if(RB4_bit && !s1flag){       //
        t1val = TMR1H;
        t1val = t1val << 8;
        t1val = t1val | TMR1L;

        tx_buf[tx_buf_head % TX_BUF_SIZE][T1_RISE] = t1val;

        s1flag = 1;
     }
     if(!RB4_bit && s1flag){      //
         t1val = TMR1H;
         t1val = t1val << 8;
         t1val = t1val | TMR1L;

          tx_buf[tx_buf_head % TX_BUF_SIZE][T1_FALL] = t1val;
          tx_buf_head++;

          s1flag = 0;
    }
  }
  if (TMR1IF_bit){
    TMR1IF_bit = 0;
    TMR1H = 0x00;
    TMR1L = 0x00;
  }
}

void main() {
    unsigned long width;
    unsigned short t1fall, t1rise;
    char txt[10];

    tx_buf_head = 0;
    tx_buf_tail = 0;

    TRISB4_bit = 1;
    OPTION_REG = 0b10001000; //Bits 0:2 prescaller rate select
    INTCON = 0b11100000;
    T1CON = 0x01;
    TMR1IE_bit = 1;
    UART1_Init(19200);

    while(1) {
        if(tx_buf_head != tx_buf_tail) {

            t1fall = tx_buf[tx_buf_tail % TX_BUF_SIZE][T1_FALL];
            t1rise = tx_buf[tx_buf_tail % TX_BUF_SIZE][T1_RISE];
            tx_buf_tail++;

            if(t1fall >= t1rise) {
                width = t1fall - t1rise;
            }
            else {
                width = (unsigned short)0 - (t1rise - t1fall);
            }

            LongToStr(width, txt);

            UART1_Write_Text(txt);
            UART1_Write(13);
        }
    }
}

volatile unsigned long t1, t2, t3;
char txt[12];
short tflag;

void Interrupt(){
  if (TMR0IF_bit){
    TMR0IF_bit = 0;
    TMR0 = 255;
    if(RB4_bit && tflag == 0){
      TMR1H         = 0x00;
      TMR1L         = 0x00;
      tflag = 1;
     }
     
     if(!RB4_bit && tflag == 1){
      t1 = TMR1H;
      t1 = t1 << 8;
      t1 = t1 | TMR1L;
      //t1 =  (TMR1H << 8) | TMR1L;
      tflag = 2;
    }
   
    if(!RB5_bit && tflag == 2) tflag = 3;
     
    if(RB5_bit && tflag == 3){
      TMR1H         = 0x00;
      TMR1L         = 0x00;
      tflag = 4;
     }
     
     if(!RB5_bit && tflag == 4){
      t2 = TMR1H;
      t2 = t2 << 8;
      t2 = t2 | TMR1L;
      tflag = 5;
    }
   
    if(!RB6_bit && tflag == 5) tflag = 6;
   
    if(RB6_bit && tflag == 6){
      TMR1H         = 0x00;
      TMR1L         = 0x00;
      tflag = 7;
     }

     if(!RB6_bit && tflag == 7){
      t3 = TMR1H;
      t3 = t3 << 8;
      t3 = t3 | TMR1L;
      LongToStr(t1, txt);
      UART1_Write_Text(txt);
      LongToStr(t2, txt);
      UART1_Write_Text(txt);
      LongToStr(t3, txt);
      UART1_Write_Text(txt);
      UART1_Write(13);
      tflag = 8;
    }
   
    if(!RB4_bit && tflag == 8) tflag = 0;
    }
}

void main() {
  OPTION_REG = 0b10001000;
  INTCON = 0b11100000;
  T1CON = 0b00000001;
  TMR1IE_bit = 1;
  UART1_Init(19200);
  Delay_ms(100);
  while(1);
}