float phi = 0; // degrees
float phir = 0; // radians (for sin func to calculate pwm)

int wave = 0;

float castprac = 0; // duty cycle (from 0 to 10000 parts)
float celcasprac = 0;
float caspraczap = 0; // duty cycle on-time

float frequencypwm = 0;

unsigned long past = 0;

float ampli = 0;

void setup() {

  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);

Serial.begin(9600);
  frequencypwm = 1000;

}

void loop() {

  if(micros() - past >= (1000000.0 / (frequencypwm))) {
    dowave((analogRead(A0) / 10.0), ((analogRead(A1) * 0.001)));
    frequencypwm = 2000;
    past = micros();
  }

    dopwm();

}

void dopwm() {

  unsigned long timefull = celcasprac * 10000;

  celcasprac = (1000000.0 / (frequencypwm));

  float casjedndiel = celcasprac / 10000.0;
  //Serial.println(casjedndiel);

  caspraczap = casjedndiel * castprac;

  if(((micros() * 10000) % timefull) <= (caspraczap * 10000)) {
    if(sin(phir) > 0) {
      fastdwrtpd(3, LOW);
      fastdwrtpd(2, HIGH);
    } else if(sin(phir) < 0) {
      fastdwrtpd(2, LOW);
      fastdwrtpd(3, HIGH);
    }
  } else if(((micros() * 10000) % timefull) > (caspraczap * 10000)) {
    if(sin(phir) > 0) {
      fastdwrtpd(2, LOW);
      fastdwrtpd(3, LOW);
    } else if(sin(phir) < 0) {
      fastdwrtpd(2, LOW);
      fastdwrtpd(3, LOW);
    }
  }

}

void dowave(int frekvlny, float velkost) {

  unsigned long cas = micros();
  float casvlny = 1000000.0 / (float)frekvlny;
  float caspolvlny = (float)casvlny / 2.0;
  float casvovlne = fmod(cas, casvlny);
  float castvlny = ((float)casvovlne / (float)casvlny);

  phi = 360 * castvlny;
  phir = (phi * 71.0) / 4068.0;

  castprac = (10000 * (velkost * (abs(sin(phir)))));

}

void fastdwrtpd(uint8_t vyvod, uint8_t hodnota) {  // only used for port D (PD0 - PD7)

if(hodnota == HIGH) {
  PORTD = PORTD | 1 << vyvod;
} else if (hodnota == LOW) {
  PORTD = PORTD & (~(1 << vyvod));
}
 
}