#include <esp32-hal-timer.h>
#define SW 23

hw_timer_t *timer = NULL;
int c = 0;

void IRAM_ATTR onTimer(){
  digitalWrite(2, !digitalRead(2));
}

void setup() {
  pinMode(2, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(18, OUTPUT);
  pinMode(19, OUTPUT);
  pinMode(SW, INPUT);

  //Internal Interrupt
  timer = timerBegin(0, 80, true);
  timerAttachInterrupt(timer, &onTimer, true);
  timerAlarmWrite(timer, 1000000, true);
  timerAlarmEnable(timer);
  timerAlarmDisable(timer);

  //External Interrupt
  //Interrupt pin, ISR function to execute, mode
  attachInterrupt(digitalPinToInterrupt(SW), onTimer, CHANGE);
  detachInterrupt(digitalPinToInterrupt(SW));
}

void loop() {
  Millis();
}

//it's seem impossible to do multiple task with loop
void Polling(){
  digitalWrite(4, !digitalRead(4));
  delay(100);
  digitalWrite(5, !digitalRead(5));
  delay(500);
  digitalWrite(2, !digitalRead(2));
  delay(1000);
  digitalWrite(18, !digitalRead(18));
  delay(1500);
  digitalWrite(19, !digitalRead(19));
  delay(2000);
}

//Internal Interrupt
void InternalInterrupt(){
  digitalWrite(4, !digitalRead(4));

  c++;
  if((c%5)==0)
    digitalWrite(5, !digitalRead(5));
  if((c%10)==0)
    digitalWrite(2, !digitalRead(2));
  if((c%15)==0)
    digitalWrite(18, !digitalRead(18));
  if((c%30)==0)
    digitalWrite(19, !digitalRead(19));
  
  if(c>30)
    c=0;
}

//External Interrupt
void ExternalInterrupt(){
  attachInterrupt(digitalPinToInterrupt(SW), onTimer, CHANGE);
}

//millis() function
unsigned long last100 = 0;
unsigned long last500 = 0;
unsigned long last1000 = 0;
unsigned long last1500 = 0;
unsigned long last3000 = 0;
void Millis(){

  if(millis() - last100 >= 100){
    last100 = millis();
    digitalWrite(4, !digitalRead(4));
  }
  if(millis() - last500 >= 500){
    last500 = millis();
    digitalWrite(2, !digitalRead(2));
  }
  if(millis() - last1000 >= 1000){
    last1000 = millis();
    digitalWrite(5, !digitalRead(5));
  }
  if(millis() - last1500 >= 1500){
    last1500 = millis();
    digitalWrite(18, !digitalRead(18));
  }
  if(millis() - last3000 >= 2000){
    last3000 = millis();
    digitalWrite(19, !digitalRead(19));
  }

}