Frequency Counter

/*
 * LCD Counter
 * Created: 12/08/2017 23:34:47
 *  Author: moty22.co.uk
*/

#include <LiquidCrystal.h>

  byte overF=0;
  unsigned long freq;
  double period;
  
   // initialize the library with the numbers of the interface pins
  LiquidCrystal lcd(12, 11, A2, A3, A4, A5);

// the setup function runs once when you press reset or power the board
void setup() {
 
    lcd.begin(16, 2);   // set up the LCD's number of columns and rows:
    
          //1 Hz timer
    OCR0A = 249;
    TCCR0A = _BV(WGM00) | _BV(WGM01) | _BV(COM0A0); //   
    TCCR0B = _BV(WGM02) | _BV(CS02) | _BV(CS01);  //  PWM mode, input T0 pin D4
    pinMode(6, OUTPUT);
    
      //250 Hz - timer2
    OCR2A =249;
    OCR2B = 125;  
    TCCR2A = _BV(COM2B1) | _BV(COM2B0) | _BV(WGM21) | _BV(WGM20);  //output B in phase, fast PWM mode
    TCCR2B = _BV(WGM22) | _BV(CS22) | _BV(CS21); // set prescaler to 256 and start the timer
    pinMode(3, OUTPUT);
    
        //  counter input T1 pin D5
    OCR1A = 32767;   //32768 counts
    TCCR1A = _BV(WGM10) | _BV(WGM11) | _BV(COM1A0); //   
    TCCR1B =_BV(WGM12) | _BV(WGM13) | _BV(CS12) | _BV(CS11); //input pin D5
    pinMode(9, OUTPUT);
    
    lcd.setCursor(7, 0); // top middle
    lcd.print("hi");

}

  
  // the loop function runs over and over again forever
void loop() {

      //wait for high
    while(digitalRead(6)){}
    while(!digitalRead(6)){}
      //start the count
    TIFR1 = _BV(OCF1A);    //reset int
    OCR1A = 32767; 
    TCNT1=0;
    overF=0;
    while(digitalRead(6)){
    if(TIFR1 & (1<<OCF1A)) {++overF; TIFR1 = _BV(OCF1A);}   //overflow 
    }
        //count end
    freq = (unsigned long)TCNT1 + ((unsigned long)overF * 32768);
    period = 1000000 / (double)freq;
    if(freq == 0){period=0;}
    
    lcd.clear();
    lcd.setCursor(3, 0); // top line
    lcd.print(freq,DEC);
    lcd.setCursor(11, 0);
    lcd.print("Hz");
    lcd.setCursor(3, 1);
    lcd.print(period,DEC);
    lcd.setCursor(10, 1);
    lcd.print(" uS   ");
}