#define BAUD 115200

//Pin connected to ST_CP of 74HC595
int latchPin = 13;
//Pin connected to SH_CP of 74HC595
int clockPin = 12;
////Pin connected to DS of 74HC595
int dataPin = 11;

byte min1=0;
byte min0=0;

byte minuto=0;



byte display0[10]= {119,65,59,107,77,110,126,67,127,111}; 

void readSerial()
 {
  if( Serial.available()) {
      minuto=Serial.read();
      if (minuto<100)
      {
        min1=minuto/10;
        min0=minuto%10;
        digitalWrite(latchPin, 0);
        shiftOut(dataPin, clockPin, display0[min1]); 
        shiftOut(dataPin, clockPin, display0[min0]); 
        digitalWrite(latchPin, 1); 
      }    
    }
  }
void setup() {
  //Start Serial for debuging purposes	
  Serial.begin(BAUD);
  //set pins to output because they are addressed in the main loop
  pinMode(latchPin, OUTPUT);  
  min1=minuto/10;
  min0=minuto%10;
  digitalWrite(latchPin, 0);
  shiftOut(dataPin, clockPin, display0[min1]); 
  shiftOut(dataPin, clockPin, display0[min0]); 
  digitalWrite(latchPin, 1);      
}

void loop() {
  readSerial();
}

void shiftOut(int myDataPin, int myClockPin, byte myDataOut) {
  // This shifts 8 bits out MSB first, 
  //on the rising edge of the clock,
  //clock idles low

//internal function setup
  int i=0;
  int pinState;
  pinMode(myClockPin, OUTPUT);
  pinMode(myDataPin, OUTPUT);

//clear everything out just in case to
//prepare shift register for bit shifting
  digitalWrite(myDataPin, 0);
  digitalWrite(myClockPin, 0);

  //for each bit in the byte myDataOut…
  //NOTICE THAT WE ARE COUNTING DOWN in our for loop
  //This means that %00000001 or "1" will go through such
  //that it will be pin Q0 that lights. 
  for (i=7; i>=0; i--)  {
    digitalWrite(myClockPin, 0);

    //if the value passed to myDataOut and a bitmask result 
    // true then... so if we are at i=6 and our value is
    // %11010100 it would the code compares it to %01000000 
    // and proceeds to set pinState to 1.
    if ( myDataOut & (1<<i) ) {
      pinState= 1;
    }
    else {	
      pinState= 0;
    }

    //Sets the pin to HIGH or LOW depending on pinState
    digitalWrite(myDataPin, pinState);
    //register shifts bits on upstroke of clock pin  
    digitalWrite(myClockPin, 1);
    //zero the data pin after shift to prevent bleed through
    digitalWrite(myDataPin, 0);
  }

  //stop shifting
  digitalWrite(myClockPin, 0);
}