#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include "lcd.h"

volatile uint8_t pcount;
volatile uint16_t paverage;
volatile uint16_t period;
volatile uint8_t stat;
 
ISR (INT0_vect)
{
TCNT0 = 0;   // CLEAR TIMER
stat = 1;   // rising edge detected int0 //
}

ISR (INT1_vect)
{
if (stat == 1)
  {
  pcount++;   // count +1 //
  paverage += TCNT0;   // counter total + counter //
  stat = 0;   // falling edge detetected int1 //
  if (pcount == 16)
    {
    period = paverage/16;   // average //
    paverage = 0;   // reset @ 16 readings//
    pcount = 0;
   }
  }
}
 
int main(void)
{
uint8_t dtemp;
DDRD = (1 << DDD7);   // Set PD7 as output //
PORTD = 0X00;
DDRB = 0xFF;   // Set Port B as output //
PORTB = 0X00;
TCCR2 = (1 << WGM20)|(1 << WGM21)|(1 << COM21)|(1 << CS20)|(1 << CS22);   // fast pwm, clk/128 //
OCR2 = 2; // 2/255 duty cycle //
MCUCR = (1 << ISC00)|(1 << ISC01)|(0 << ISC10)|(1 << ISC11);   // INT0 RISING EDGE + INT1 FALLING EDGE//
GICR = (1 << INT0)|(1 << INT1);   // INT0/INT1 ACTIVATED //
TCCR0 = (1 << CS00)|(1 << CS01);   // NORMAL COUNT & START & CLOCK/64 //
lcd_init();   // LCD INIT //
lcd_control(1,0,0);   // LCD INIT //
sei();   // ENABLE INTERRUPTS //
while (1)
  {
  lcd_goto(0x40);
  print5 (pcount);   // PRINT COUNTER VALUE TO LCD //
  dtemp = period * 0.436608;   // distance measure (inches) //
  lcd_goto(0x00);                 
  print3 (period);   // PERIOD VALUE TO LCD //
  lcd_goto(0x06);                 
  print3 (dtemp);   // DISTANCE VALUE TO LCD //
  }
}