DevHeads IoT Integration ServerDIIS
DevHeads IoT Integration Server•2y ago
Marvee Amasi

How can I run independent tasks on separate cores using ESP-IDF on ESP32?

Hey @Middleware & OS coding gurus 👩‍💻, There is this thing I want to fully understand.
I'm working with ESP-IDF on an ESP32 and trying to run two independent tasks simultaneously on separate cores. Look how I did it using 
C
👇👇:

xTaskCreatePinnedToCore(sensorsTask, "Sensor", 5000, 0, 0, &sensorTaskHandler, 0);

xTaskCreatePinnedToCore(storageTask, "Storage", 5000, 0, 0, &storageTaskHandler, 1);

void storageTask() {
  for (;;) {
    gpio_set_level(4, 1); 
// Turn on LED on pin 4
    gpio_set_level(2, 0); 
// Turn off LED on pin 2
  }
}

void sensorsTask() {
  for (;;) {
    gpio_set_level(2, 1); 
// Turn on LED on pin 2
    gpio_set_level(4, 0); 
// Turn off LED on pin 4
  }
}


The expected behavior is for both LEDs to be constantly lit. However, they are flickering, I think the tasks are running one core at a time. Adding 
vTaskDelay(1)
in both tasks resolves the issue.

But my question is:

  • Why are the LEDs flickering even though the tasks are assigned to separate cores and should be running concurrently?
  • Why is the delay necessary if both cores are supposedly operating independently?
    I understand that the delay allows for context switching between tasks, but shouldn't that be handled by the FreeRTOS scheduler with two cores available?
Was this page helpful?