const int CP = 3; //Collegamento clck pulse
const int PL = 4; //Collegamento Parallel Load
const int start = 5; //Collegamento
const int numBit = 6;
const int numShift = 9; //Idle1-Start0-d0..d5-Stoop1

int8_t shift_count;
uint32_t m0;

#define BAUD 104

void setup() {
  Serial.begin(9600);
  //Serial.println(RAMEND, HEX);
  //Serial.print(SPH, HEX);
  //Serial.println(SPL, HEX);
  
  pinMode(start, INPUT_PULLUP);
  pinMode(CP, OUTPUT);
  pinMode(PL, OUTPUT);
  digitalWrite(PL, HIGH); 
  digitalWrite(CP, HIGH);
  shift_count=0;
  load_SR();


}

void loop() {
  shift_count= shifter(shift_count);
  

}

void load_SR(){
  //Per generare un impulso brevissimo e caricare i bit nello shift register
  digitalWrite(PL, HIGH);
  digitalWrite(PL, LOW);
  digitalWrite(PL, HIGH);
}

int8_t shifter(int8_t c){
  if(c){
    uint32_t mx = millis();
    if((mx-m0) > BAUD){
      m0 += BAUD;
      digitalWrite(CP, LOW);
      digitalWrite(CP, HIGH);
      digitalWrite(CP,LOW);
      c--;

    }

  } else {
    if(digitalRead(start) == 0){ //perchè pull-up
      m0 = millis();
      load_SR();
      c = numShift;
    }

  } 
  return c;

}