When running the HID keyboard example for the freedom K22 board the "Device Task" is given a priority 13. Per AN3905, I was under the impression that these types of system tasks were given priorities 0 - 8 and that creation of user tasks with higher priority numbers would assure that system tasks would continue to execute. In usb_dev.c the task is created using USB_DEVICE_TASK_PRIORITY which is defined as 6, but then the task creation goes through the OSA layer for MQX which adds 7 (presumably to prevent conflicts with system tasks), resulting in a priority of 13. Is this what is intended?
The reason I'm asking is that I created a long running task at priority 12 and it prevented enumeration by blocking the device task. What priority do I need to set user tasks to in order to be assured that no system tasks are blocked?