#define CONFIG_FREERTOS_HZ 1000
SemaphoreHandle_t myFirstSem;

#define MUTEX

void
t1 (void *parameter)
{
  for (;;)
    {
#ifdef MUTEX
      if (xSemaphoreTake (myFirstSem, (TickType_t) 1000) == pdTRUE)
	{
	  // yep got it
	  Serial.print ("ABCDEFGHIJKLMNOPQRST\n");
	  xSemaphoreGive (myFirstSem);
	}
#else
      Serial.print ("ABCDEFGHIJKLMNOPQRST\n");	// no mutex
#endif
    }
}

void
t2 (void *parameter)
{
  for (;;)
    {
#ifdef MUTEX
      if (xSemaphoreTake (myFirstSem, (TickType_t) 1000) == pdTRUE)
	{
	  // yep got it
	  Serial.print ("abcdefghijklmnopqrst\n");
	  xSemaphoreGive (myFirstSem);
	}
    }
#else
      Serial.print ("abcdefghijklmnopqrst\n");
#endif
    }

  void setup ()
  {
    Serial.begin (112500);
    vTaskDelay (1000 / portTICK_PERIOD_MS);

#ifdef MUTEX
    // create sem before you start tasks
    myFirstSem = xSemaphoreCreateMutex ();	// 1 key present
#endif

    vTaskPrioritySet (NULL, 10);	// so it dont loose cpu

    xTaskCreate (t1, "t1", 10000, NULL, 2, NULL);
    xTaskCreate (t2, "t1", 10000, NULL, 2, NULL);
    Serial.println ("just bef");

    vTaskDelete (NULL);		// main or loop quit
  }

  void loop ()
  {
  }