#include "esp32-hal-timer.h"

hw_timer_t *timer = NULL;

void IRAM_ATTR blink() { digitalWrite(22,!digitalRead(22 ));}

void setup() {
  Serial.begin(115200);
  Serial.println("Hello ESP32");
  pinMode(23, OUTPUT); // Red Led
  pinMode(22, OUTPUT); // Blue Led
  pinMode(32, INPUT_PULLDOWN); //Pushbutton 

  timer = timerBegin(100000); //1 ms
  if(timer == NULL) {
    Serial.println("Timer initialization failed!");
    while(1); //Stop if timer failed
  }
  timerAttachInterrupt(timer, &blink); //Attach blink ISR
  timerWrite(timer, 0);
  //Set alarm, triggering every million ticks = 1s
  timerAlarm(timer, 1000000, true, 0);
  timerStart(timer); //Start timer
  Serial.println("Timer started");
}

void loop() {
  digitalWrite(23, digitalRead(32));
}