// step motor clock
// skalgo, 2016

// 4096 kroków/obrót

int P0 =  9;
int P1 = 10;
int P2 = 11;
int P3 = 12;
int _step=0;

unsigned long int start;
int step=0;

void setup() 
{
  Serial.begin(9600);
  pinMode(P0,OUTPUT);
  pinMode(P1,OUTPUT);
  pinMode(P2,OUTPUT);
  pinMode(P3,OUTPUT);
  pinMode(2,INPUT_PULLUP);
  start=millis();
} 

const unsigned char bit[]={1,2,4,8,16,32,64,128};

void do_step(byte st)
{
  byte b;
  
  switch(_step)
  {
    case 0: b=0b1000; break;
    case 1: b=0b1100; break;
    case 2: b=0b0100; break;
    case 3: b=0b0110; break;
    case 4: b=0b0010; break;
    case 5: b=0b0011; break;
    case 6: b=0b0001; break;
    case 7: b=0b1001; break;
  }

  digitalWrite(P0,(b&bit[0])==bit[0]);
  digitalWrite(P1,(b&bit[1])==bit[1]);
  digitalWrite(P2,(b&bit[2])==bit[2]);
  digitalWrite(P3,(b&bit[3])==bit[3]);

  delay(5);

  digitalWrite(P0,LOW);
  digitalWrite(P1,LOW);
  digitalWrite(P2,LOW);
  digitalWrite(P3,LOW);

  _step--; 

  if(_step<0)
    _step=7;

  if(st)
  {
    step++;

    if(step==4096)
    {
      start=millis();
      step=0;
    }
  }
}

void loop() 
{
  float m;
  float n=86400000.0/4096.0*((float)step+1.0);

  do
  {
    if(millis()<start)
      m=(0xffffffff-start)+millis();
    else
      m=millis()-start;

    if(digitalRead(2))
      do_step(0);
    else
      delay(10);
  }while(m<n);

  do_step(1);
}