How tasks/Timer could wok on ARM-CM3/4

Kernel
3

Thanks Richard,
I follow your suggestion to check xPortSysTickHandler(), the handler has been triggered by every 1ms after I configure the Systick.
But task/time still not work, my example is very simple as below.


=============================================================
tatic void vTestTask(void *pvParameters)
{
    while (1) {
        vTaskDelay(1000);
	printf("1s for tasks delay !!!\r\n");
	//print something for every 1 second
    }
}
void vTimerCallback( TimerHandle_t xTimer )
{
    //print something in here
    printf("20s for timer timeout !!!\r\n");
}
=============================================================
 {
    xReturn = xTaskCreate(vTestTask, FREERTOS_EXAMPLE_TASK_NAME, 
                                            FREERTOS_EXAMPLE_TASK_STACKSIZE / 
                                            sizeof(portSTACK_TYPE), (void *)NULL, 
                                            FREERTOS_EXAMPLE_TASK_PRIO, NULL);
    if ( xReturn != pdPASS )
        printf("Create Task Fail, result=%d!!!\r\n", xReturn);
    else
        printf("Create Task Sus !!!\r\n");

    //create timer
    xTimers_test = xTimerCreate
                   ( /* Just a text name, not used by the RTOS
                     kernel. */
                     "Timer",
                     /* The timer period in ticks, must be
                     greater than 0. */
                     20000, //20 second
                     /* The timers will auto-reload themselves
                     when they expire. */
                     pdTRUE,
                     /* The ID is used to store a count of the
                     number of times the timer has expired, which
                     is initialised to 0. */
                     ( void * ) 0,
                     /* Each timer calls the same callback when
                     it expires. */
                     vTimerCallback
                   );
    if ( xTimers_test != NULL )
    {   
        xTimerStart(xTimers_test,0);
        printf("Create Timer Sus !!!\r\n");
    }
    else
        printf("Create Timer Fail !!!\r\n");
}
=============================================================

I has already trace the source of FreeRTOS to look at “xTaskIncrementTick()” function, it seems the return is always pdFALSE.
Could you have any suggestion then I could verify it ? Thanks.