hw_timer_t *timer1 = NULL;
hw_timer_t *timer2 = NULL;
unsigned int resetTimer = 0;
volatile int counter = 0;

void IRAM_ATTR onTimer800(){
    counter = counter+1;
}

void IRAM_ATTR onTimer500(){
    counter = counter-1;
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
    timer1 = timerBegin(0, 40, true);
    timerAttachInterrupt(timer1, &onTimer800, true);
    timerAlarmWrite(timer1, 800000, true);
    timerAlarmEnable(timer1);

    timer2 = timerBegin(1, 40, true);
    timerAttachInterrupt(timer2, &onTimer500, true);
    timerAlarmWrite(timer2, 500000, true);
    timerAlarmEnable(timer2);
}
void loop() {
  unsigned int time=millis();
  Serial.print("\n");
  Serial.print("Detik : ");
    Serial.print(time); 
    Serial.print(" , Counter: ");
    Serial.print(counter);
  delay (100);

  // put your main code here, to run repeatedly:
}