Scheduler - yield()

yield();

#include <Scheduler.h>

int counter = 0;
int counter1 = 0;

void setup() {
  Serial.begin(9600);
  Scheduler.startLoop(loop1);
}

void loop () {
 analogWrite(9, counter);
 counter++;

 if (counter > 255){
  counter = 0;
 }

 delay(33);
}

void loop1 () {
 if (Serial.available()) {
    char c = Serial.read();

    if (c=='0') {
      digitalWrite(2, LOW);
      Serial.println("Led turned OFF!");
    }

    if (c=='1') {
      digitalWrite(2, HIGH);
      Serial.println("Led turned ON!");
    }
  }

 yield();
}