#include <avr/io.h>
#include <avr/interrupt.h>

const int LED_pin = 13; 
const int tlac1 = A0;

int stav_tlac1;
int lastState = HIGH;


unsigned int reload = 0xF424;   // dec 62 500
volatile int sec;
volatile int min;
volatile int hod;

ISR(TIMER1_COMPA_vect)		//obsluha vektoru přerušeni od čítače 
{
   sec++;			// pricte impuls do citace vterin
   flash();			//neguje led

   if(sec==5)		//
	 {
	 sec = 0;
	 min=min+1;		// pricte minutu do promene minut
         }
   if(min>=10)
	 {
	 min = 0; 
	 hod=hod+1; 
	 }
   if(hod==24)
      {
      hod=0;
      }
}	//konec preruseni

void setup()		//------------------------------------------------------------------------------
{
   pinMode(LED_pin, OUTPUT);		//nastaveni portu na vystup
   pinMode(tlac1, INPUT_PULLUP);
   digitalWrite(LED_pin, LOW);		//zhasne led
   cli();
   TCCR1A = 0;				
   TCCR1B = 0; 
   OCR1A = reload;				// porovnavaci registr - zadani hodnoty 62 500
   TCCR1B = (1<<WGM12) | (1<<CS12); 	// delicka hodin
   TIMSK1 = (1<<OCIE1A); 			// povoleni interrupt preteceni citace
   sei(); 					// povoleni vsech interruptů
}					//konec setup

void loop()		//-----------------------------------------------------------------------------------
{
   stav_tlac1 = digitalRead(tlac1);
   if (lastState == HIGH && stav_tlac1 == LOW)
   {
   min = min + 1;
   }
   lastState = stav_tlac1;
   delay(100);
}		//konec loop



void flash()		//funkce bliknuti_negace led ------------------------------------------------
{
   static boolean output = HIGH;
   digitalWrite(LED_pin, output);
   output = !output;
}