#define GAP_DELAY 1000
#define DWELL 3
#define SPARK_DELAY 30
#define C1 12
#define C2 11
#define C3 10
#define C4 9

#define POTENTIOMETER_PIN 0

// int  rpm_table = [4.5, 4, 3.5, 3, 2.5]; // corresponding dwell to rpm 1000, 2000, 3000, 4000, 5000
int START_DELAY=2000;
bool cranking = true;

void setup() {
  pinMode(C1, OUTPUT);
  pinMode(C2, OUTPUT);
  pinMode(C3, OUTPUT);
  pinMode(C4, OUTPUT);
}

void loop() {
    if(cranking) {
      delay(START_DELAY);
      cranking = false; // if ign NE is true, set tdc to false
      // engine idle is over 400 rpm
    }
    
    Serial.println(analogRead(POTENTIOMETER_PIN));
    // Q: how do you know an engine is not on cranking state? prolly using signal from distributor
    // that tells the spark is generated
    // if(ignitionSignal) { // ignition signal 

    // }

    
  
    digitalWrite(C1, HIGH);
    delay(DWELL);
    digitalWrite(C1, LOW);
    delay(SPARK_DELAY);

    digitalWrite(C2, HIGH);
    delay(DWELL);
    digitalWrite(C2, LOW);
    delay(SPARK_DELAY);

    digitalWrite(C3, HIGH);
    delay(DWELL);
    digitalWrite(C3, LOW);
    delay(SPARK_DELAY);

    digitalWrite(C4, HIGH);
    delay(DWELL);
    digitalWrite(C4, LOW);

    delay(GAP_DELAY);
}