#define PWM1_PIN PA8
#define PWM2_PIN PA6

#define CAPTURE1_PIN PA0
#define CAPTURE2_PIN PA1

volatile uint32_t rise1 = 0;
volatile uint32_t period1 = 0;

volatile uint32_t rise2 = 0;
volatile uint32_t period2 = 0;

bool lastState1 = LOW;
bool lastState2 = LOW;

bool pwm2State = false;

uint32_t lastToggle = 0;

void setup()
{
  Serial.begin(115200);

  pinMode(PWM1_PIN, OUTPUT);
  pinMode(PWM2_PIN, OUTPUT);

  pinMode(CAPTURE1_PIN, INPUT);
  pinMode(CAPTURE2_PIN, INPUT);

  /* Hardware PWM : 100Hz */

  analogWriteFrequency(100);

  analogWrite(PWM1_PIN, 128);
}

void loop()
{
  /* Software 500Hz generation */

  if(micros() - lastToggle >= 1000)
  {
    lastToggle = micros();

    pwm2State = !pwm2State;

    digitalWrite(PWM2_PIN, pwm2State);
  }

  measureInput1();

  measureInput2();

  static uint32_t lastPrint = 0;

  if(millis() - lastPrint >= 1000)
  {
    lastPrint = millis();

    float freq1 = 0;
    float freq2 = 0;

    if(period1 > 0)
      freq1 = 1000000.0 / period1;

    if(period2 > 0)
      freq2 = 1000000.0 / period2;

    Serial.print("Freq1 = ");

    Serial.print(freq1);

    Serial.print(" Hz    ");

    Serial.print("Freq2 = ");

    Serial.print(freq2);

    Serial.println(" Hz");
  }
}

/* -------- Measure CH1 -------- */

void measureInput1()
{
  bool currentState = digitalRead(CAPTURE1_PIN);

  if(currentState == HIGH && lastState1 == LOW)
  {
    uint32_t now = micros();

    period1 = now - rise1;

    rise1 = now;
  }

  lastState1 = currentState;
}

/* -------- Measure CH2 -------- */

void measureInput2()
{
  bool currentState = digitalRead(CAPTURE2_PIN);

  if(currentState == HIGH && lastState2 == LOW)
  {
    uint32_t now = micros();

    period2 = now - rise2;

    rise2 = now;
  }

  lastState2 = currentState;
}