void vTask1( void * pvParameters )
{
     for(;; )
     {
         // Task code goes here.

         // ...

         // At some point the task wants to perform a long operation during
         // which it does not want to get swapped out.  It cannot use
         // taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
         // operation may cause interrupts to be missed - including the
         // ticks.

         // Prevent the RTOS kernel swapping out the task.
         vTaskSuspendAll ();

         // Perform the operation here.  There is no need to use critical
         // sections as we have all the microcontroller processing time.  
         // During this time interrupts will still operate and the RTOS kernel
         // tick count will be maintained.

         // ...

         // The operation is complete.  Restart the RTOS kernel.
         xTaskResumeAll ();
     }
}