请问我这么写的任务通知功能代码哪里有问题？

INIUKA

如果不用这个任务通知的话，任务可以自动切换执行，现在加了通知，没有输出了

yklstudent

static TaskHandle_t xTaskToNotify = NULL;

/* The peripheral driver's transmit function. */
void StartTransmission( uint8_t *pcData, size_t xDataLength )
{
    /* At this point xTaskToNotify should be NULL as no transmission is in
    progress.  A mutex can be used to guard access to the peripheral if
    necessary. */
    configASSERT( xTaskToNotify == NULL );

    /* Store the handle of the calling task. */
    xTaskToNotify = xTaskGetCurrentTaskHandle();

    /* Start the transmission - an interrupt is generated when the transmission
    is complete. */
    vStartTransmit( pcData, xDatalength );
}
/*-----------------------------------------------------------*/

/* The transmit end interrupt. */
void vTransmitEndISR( void )
{
BaseType_t xHigherPriorityTaskWoken = pdFALSE;

    /* At this point xTaskToNotify should not be NULL as a transmission was
    in progress. */
    configASSERT( xTaskToNotify != NULL );

    /* Notify the task that the transmission is complete. */
    vTaskNotifyGiveFromISR( xTaskToNotify, &xHigherPriorityTaskWoken );

    /* There are no transmissions in progress, so no tasks to notify. */
    xTaskToNotify = NULL;

    /* If xHigherPriorityTaskWoken is now set to pdTRUE then a context switch
    should be performed to ensure the interrupt returns directly to the highest
    priority task.  The macro used for this purpose is dependent on the port in
    use and may be called portEND_SWITCHING_ISR(). */
    portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/

/* The task that initiates the transmission, then enters the Blocked state (so
not consuming any CPU time) to wait for it to complete. */
void vAFunctionCalledFromATask( uint8_t ucDataToTransmit, size_t xDataLength )
{
uint32_t ulNotificationValue;
const TickType_t xMaxBlockTime = pdMS_TO_TICKS( 200 );

    /* Start the transmission by calling the function shown above. */
    StartTransmission( ucDataToTransmit, xDataLength );

    /* Wait for the transmission to complete. */
    ulNotificationValue = ulTaskNotifyTake( pdFALSE, xMaxBlockTime );

    if( ulNotificationValue == 1 )
    {
        /* The transmission ended as expected. */
    }
    else
    {
        /* The call to ulTaskNotifyTake() timed out. */
    }
}
这是官网范例，按照范例来写