hw_timer_t * timer0 = NULL;
hw_timer_t * timer1 = NULL;
portMUX_TYPE timerMux0 = portMUX_INITIALIZER_UNLOCKED;
portMUX_TYPE timerMux1 = portMUX_INITIALIZER_UNLOCKED;

volatile uint8_t led1stat = 0; 
volatile uint8_t led2stat = 0; 

void IRAM_ATTR onTimer0(){
  portENTER_CRITICAL_ISR(&timerMux0);
  led1stat=1-led1stat;
  digitalWrite(15, led1stat);  
  portEXIT_CRITICAL_ISR(&timerMux0);
}

void IRAM_ATTR onTimer1(){
  // Critical Code here
  portENTER_CRITICAL_ISR(&timerMux1);
  led2stat=1-led2stat;
  digitalWrite(2, led2stat);  
  portEXIT_CRITICAL_ISR(&timerMux1);
}

void setup() {
  Serial.begin(115200);

  pinMode(2, OUTPUT);
  pinMode(15, OUTPUT);
  digitalWrite(2, LOW);    
  digitalWrite(15, LOW);    
  Serial.println("start timer 1");
  timer1 = timerBegin(1, 80, true);  
  timerAttachInterrupt(timer1, &onTimer1, true);  
  timerAlarmWrite(timer1, 250000, true); 

  Serial.println("start timer 0");
  timer0 = timerBegin(0, 80, true); 
  timerAttachInterrupt(timer0, &onTimer0, true); 
  timerAlarmWrite(timer0, 2000000, true); 

  timerAlarmEnable(timer0); 
  timerAlarmEnable(timer1); 
}

void loop() {
  vTaskDelay(portMAX_DELAY); 
}