main_handover.c

/**
 * Adapted from: https://www.freertos.org/RTOS_Task_Notification_As_Binary_Semaphore.html
*/

#include <stdio.h>
#include <pthread.h>

#include "FreeRTOS.h"
#include "semphr.h"

#define TASK_LOOP_DELAY 10

TaskHandle_t task4 = NULL;

void handover_task1(void *_)
{
    uint16_t c1 = 0;
    while (1)
    {
        c1++;
        vTaskDelay(pdMS_TO_TICKS(TASK_LOOP_DELAY));
    }
}

void handover_task2(void *_)
{
    uint16_t c2 = 0;
    while (1)
    {
        c2++;
        vTaskDelay(pdMS_TO_TICKS(TASK_LOOP_DELAY));
    }
}

void handover_task3(void *_)
{
    uint16_t c3 = 1;
    while (1)
    {
        c3 = c3 << 1;
        printf("C3: %hu\r\n", c3);

        if (c3 == 0) // Overflow
        {
            c3 = 1;                 // Reset counter
            xTaskNotifyGive(task4); // Notify task4 to wake.
        }
        vTaskDelay(pdMS_TO_TICKS(TASK_LOOP_DELAY));
    }
}

void handover_task4(void *_)
{
    uint16_t c4 = 0;
    while (1)
    {
        ulTaskNotifyTake(0, portMAX_DELAY);
        printf("[4] UP\r\n");
        c4++;
        vTaskDelay(pdMS_TO_TICKS(TASK_LOOP_DELAY));
    }
}

void main_handover()
{
    xTaskCreate(handover_task1, "T1", configMINIMAL_STACK_SIZE, NULL, 1, NULL);
    xTaskCreate(handover_task2, "T2", configMINIMAL_STACK_SIZE, NULL, 1, NULL);
    xTaskCreate(handover_task3, "T3", configMINIMAL_STACK_SIZE, NULL, 3, NULL);
    xTaskCreate(handover_task4, "T4", configMINIMAL_STACK_SIZE, NULL, 3, &task4);
    vTaskStartScheduler();

    for (;;)
        ;
}