const int pb1 = 6;
const int pb2 = 21;

const int led1 = 3;
const int led0 = 13;

unsigned long currentTime = 0;
volatile bool buttonPressed = false;

void setup() {
  // put your setup code here, to run once:
  pinMode(pb1, INPUT_PULLUP);
  pinMode(pb2, INPUT_PULLUP);//interrupts

  pinMode(led1, OUTPUT);
  pinMode(led0, OUTPUT);

  attachInterrupt(digitalPinToInterrupt(pb2), blinkISR, FALLING);
}

void loop() {
  // put your main code here, to run repeatedly:
  
  blink(led0, 300);
  //blink(led0, 300);
  ctrLED();
  if(buttonPressed)
  {
      buttonPressed = false;
      digitalWrite(led1, HIGH);
  }


}

void blink_block(int led, long interval) 
{
    digitalWrite(led, HIGH);
    delay(interval);
    digitalWrite(led, LOW);
    delay(interval);
}

void blink(int led, long interval) 
{
    if(millis() - currentTime >= interval)
    {
      currentTime = millis();
      digitalWrite(led, !digitalRead(led));//trun state according current state
    } 
}

void ctrLED(void)
{
    if(digitalRead(pb1) == LOW)
  {
    digitalWrite(led1, HIGH);
  }
  else
  {
    digitalWrite(led1, LOW);
  }
}

void blinkISR()
{
  buttonPressed = true; 
}