ATtiny2313 countdown timer

avrdude script: 
#avrdude -c usbasp -p t2313
avrdude -c usbasp -p t2313 -Uflash:w:attiny2313.hex:a

ATTiny2313 C program:

#include 
#include 
#include 
#include 

ISR(INT0_vect) {
    //PORTD &= ~(1<}

//ISR(INT1_vect) {
//    PORTD &= ~(1
int cSeconds = 0;
//   char cSecondsIni = 0;
char cStart = 0;
char cSecondsDelay = 0;
char toggle = 0;
char cBuzzerCount = 0;
//decgafb
//0100001
char cData[10]={
        0b00001000, //0
        0b01101110, //1
        0b00010010, //2
        0b00100010, //3
        0b01100100, //4
        0b00100001, //5
        0b00000001, //6
        0b01101010, //7
        0b00000000, //8
        0b00100000  //9
};

void checkTimer(void)
{

    if (TIFR & 0x01) {      // timer timed out?
          TIFR |= 0x01;       // reset timer flag
          if(toggle++>3)
          {
              toggle = 0;
              if(cStart)
              {
                  cSeconds--;
                  if(cSeconds < 0)
                  {
                      cSeconds = 0;
                  }
              }
              if(cStart == 0)
              {
                  cSecondsDelay++;
              } else {
                  cSecondsDelay = 0;
              }
              soundIfBuzzer();
          }
    }

}

//-------------------
void listenKeys(void)
{
    if((PIND & 1<        cSeconds-=60;

    if((PIND & 1<        cSeconds+=60;

    if((PIND & 1<        cSeconds-=600;

    if((PIND & 1<        cSeconds+=600;

    if(cSeconds < 0)
        cSeconds = 5940;

    if(cSeconds > 5940)
    {
        cSeconds = 0;
    }

    if((PIND & 1<    {
        if(cStart <= 0 && cSeconds > 0)
            cStart = 1;
        cBuzzerCount = 0;
    }

    while( (PIND & 1<    {
        _delay_ms(50);
        cStart = 0;
        cSecondsDelay = 0;
        cBuzzerCount = 0;
    }

}

//--------------------
void showSeconds(void)
{
      char c1 = cSeconds /60 /10;
    char c2 = cSeconds /60 %10;
    PORTB = cData[c2];
    PORTA |= 1<    PORTA &= ~(1<    _delay_ms(1);
    PORTB = cData[c1];
    PORTA |= 1<    PORTA &= ~(1<}

//-------------------------------
void sleepMode(char seconds_)
{
    if(cBuzzerCount > 0)
        seconds_ = 30;

      if(cSecondsDelay < seconds_)
          return;

      cSecondsDelay = 0;

      //indicator
      PORTA &= ~(1<      PORTA &= ~(1<
      //buzzer
      PORTD &= ~(1<      cBuzzerCount = 0;

    //#define SLEEP_MODE_IDLE         0
    //#define SLEEP_MODE_PWR_DOWN     (_BV(SM0) | _BV(SM1))
    //#define SLEEP_MODE_STANDBY только при установке внешнего резонатора
      //sei();
      set_sleep_mode(SLEEP_MODE_PWR_DOWN);
      sleep_enable();
      //sleep_cpu();
      sleep_mode();
      sleep_disable();
}

//--------------
void soundIfBuzzer(void)
{
     if(cSeconds <= 0 && cStart == 1)
      {
          cBuzzerCount = 1;
          cStart = 0;
      }

    if(cBuzzerCount > 0)
    {
        PORTD |= 1<        _delay_ms(100);
        PORTD &= ~(1<        _delay_ms(100);
        PORTD |= 1<        _delay_ms(100);
        PORTD &= ~(1<    }
}

//--------------
int main(void) {
    sei();
    // enable external interrupt 0
    GIMSK |= (1 << INT0);
    //GIMSK |= (1 << INT1);

    //PIND0:IN: +
    //PIND1:IN: -
    //PIND2:IN: start/stop
    //PIND3:
    //PIND4:IN: +
    //PIND5:IN: -
    //PIND6:OUT:LED/buzzer
    DDRD  = 0b01000000;
    PORTD = 0b00111111;

    //indicator
    DDRB = 0xFF;
    PORTB = 0x00;

    //indicator power
    DDRA = 0xFF;
    PORTA = 0xFF;

    TCCR0A = 0x02;      // Clear Timer on Compare Match (CTC) mode
    OCR0A  = 194;      // number to count up to
    TCCR0B = 0x05;      // clock source CLK/1024, start timer

    while(1) {
        checkTimer();
        listenKeys();
        showSeconds();
        sleepMode(5);
        _delay_ms(1);
    }

    return 0;}