#define DSpin 2
#define LATCHpin 3
#define CLOCKpin 4

uint16_t cislo=0;
uint8_t segment[]={1,2,4,8};
const uint8_t cifry[]={
0b00000011,//0
0b10011111,//1
0b00100101,//2
0b00001101,//3
0b10011001,//4
0b01001001,//5
0b01000001,//6
0b00011111,//7
0b00000001,//8
0b00001001,//9
0b11111111 //-
};

unsigned long previousMillis=0;

void setup() {
pinMode(DSpin, OUTPUT);
pinMode(LATCHpin, OUTPUT);
pinMode(CLOCKpin, OUTPUT);
}

void loop() {
  unsigned long currentMillis=millis();
  zobrazCislilcu(cislo);
  if(currentMillis-previousMillis>=500){
    previousMillis=currentMillis;
    cislo=(cislo+1)%10000;
  }
    
}

int i=0;
bool smer=true;

void zobrazCislilcu(int cislo){
  for(int i=0;i<4;i++){
    uint8_t cifra=cislo%10;
    cislo/=10;
    digitalWrite(LATCHpin, HIGH);
    shiftOut(DSpin,CLOCKpin,LSBFIRST,cifry[cifra]);
    shiftOut(DSpin,CLOCKpin,MSBFIRST,segment[i]);
    digitalWrite(LATCHpin, LOW);
  }
}