//settings//
int FIRSTCOIL = 2; /*DEPENING ON WHICH INJECTOR IS USED FOR SYNC
                    *INJ1 = 2 
                    *INJ2 = 4 
                    *INJ3 = 1 
                    *INJ4 = 3
                    */
int DWELL     = 2000; // INITIAL DWELL IN MICROSECONDS //
int MAXDWELL  = 2000; // MAX DWELL IN MICROSECONDS FOR MAPPING WITH RPM //
int MINDWELL  = 1500; // MIN DWELL IN MICROSECONDS FOR MAPPING WITH RPM //
//settings//
int led = 13;

int inj_flag;
int coil_flag;
int NEXTCOIL;
int RPM;
long CLK_DWELL = 65535-(DWELL*2); //math
  
void setup() {
  //Serial.begin(9600);
  //ATmega328 setup...
  TCCR1A = 0;                                 //DONT TOUCH
  TCCR1B = 0;                                 //DONT TOUCH
  TCCR1B |=(0<<CS10) | (1<<CS11) | (0<<CS12); //DONT TOUCH
  TIMSK1 |=(1<<TOIE1);                        //DONT TOUCH

  //PORT SETUP
  /*OUTPUT*/DDRA = B00001111; //p,p,p,D12,p,D10,p,D8
  /*INPUT*/DDRL = B00000000; //p,D6,p,p,p,p,p,p
  pinMode(led, OUTPUT);
}

ISR(TIMER1_OVF_vect){
  if(coil_flag == 1)
  {
    PORTA &= !B00001111; 
    inj_flag=0;
    coil_flag=0;
    
  
    TCNT1=0;}
}

void loop() {

  if ((PINL >> 0 & B00000010 >> 0) == LOW && inj_flag == 0 ) {  
  NEXTCOIL=FIRSTCOIL;
  digitalWrite(led, HIGH);
    inj_flag=1;
  } 

  if ((PINL >> 0 & B00000001 >> 0) == LOW && coil_flag == 0) {
    switch(NEXTCOIL)
    {
      case 1: PORTA |= B00000001;
        NEXTCOIL=3;
        break;
      case 2: PORTA |= B00000010;
        NEXTCOIL=1;
        break;
      case 3: PORTA |= B00000100;
        NEXTCOIL=4;
        break;
      case 4: PORTA |= B00001000;
        NEXTCOIL=2;
        break;
    }
  TCNT1 = CLK_DWELL;
    coil_flag=1;
  }
}