FreeRtosTasks.ino

Runs FreeRTOS tasks side by side. Needs Tools > Operating System > FreeRTOS (SMP).

setup() starts two tasks: one blinks the LED, the other prints a count. loop() is a task too; every five seconds it prints the list of tasks with vTaskListTasks(). Each task waits with vTaskDelay() (delay() does the same with FreeRTOS), which leaves the cores free for the others. See FreeRTOS.

Output

Serial Monitor at 115200 baud: a "countTask on core 0: n" or "countTask on core 1: n" line every second (the count task may run on either core), and every five seconds one line per task: loop, blink, count, the two idle tasks IDLE0 and IDLE1, and the FreeRTOS timer task Tmr Svc. The columns:

Column	Meaning
Name	Task name
State	X running, R ready, B blocked (waiting), S suspended, D deleted
Prio	Priority, 0 (idle) to 55
Stack	The least free stack the task has had, in 4-byte words: near 0 means too small
Num	Task number, in order of creation
Cores	Cores the task may run on: 0x1 core 0, 0x2 core 1, 0xffffffff either

// Runs FreeRTOS tasks side by side. Needs Tools > Operating System > FreeRTOS (SMP).
//
// setup() starts two tasks: one blinks the LED, the other prints a count.
// loop() is a task too; every five seconds it prints the list of tasks, with
// the cores each one is allowed on (0x1 core 0, 0x2 core 1, 0xffffffff
// either). Each task waits with vTaskDelay() (delay() does the same with
// FreeRTOS), which leaves the cores free for the others.
 
#include <FreeRTOS.h>
#include <task.h>
 
void blinkTask(void*) {
    pinMode(LED_BUILTIN, OUTPUT);
    for (;;) {
        digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
        vTaskDelay(pdMS_TO_TICKS(250));
    }
}
 
void countTask(void*) {
    unsigned long count = 0;
    for (;;) {
        Serial.print("countTask on core ");
        Serial.print(rp2040.cpuid());
        Serial.print(": ");
        Serial.println(count++);
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}
 
void setup() {
    Serial.begin(115200);
    while (!Serial) {}
    // Function, name, stack (in 4-byte words), parameter, priority, handle.
    xTaskCreate(blinkTask, "blink", 512, nullptr, 1, nullptr);
    xTaskCreate(countTask, "count", 1024, nullptr, 1, nullptr);
}
 
void loop() {
    static char list[640];
    vTaskListTasks(list, sizeof(list));
    Serial.println("Name           \tState\tPrio\tStack\tNum\tCores");
    Serial.print(list);  // State: X running, R ready, B blocked, S suspended; Stack: least free, in words
    Serial.println();
    delay(5000);
}