Creates a new queue instance, and returns a handle by which the new queue can be referenced.
Internally, within the FreeRTOS implementation, queues use two blocks of memory. The first block is used to hold the queue's data structures. The second block is used to hold items placed into the queue. If a queue is created using xQueueCreate() then both blocks of memory are automatically dynamically allocated inside the xQueueCreate() function. (see http://www.freertos.org/a00111.html). If a queue is created using xQueueCreateStatic() then the application writer must provide the memory that will get used by the queue. xQueueCreateStatic() therefore allows a queue to be created without using any dynamic memory allocation.
uxQueueLengthThe maximum number of items that the queue can contain.
uxItemSizeThe number of bytes each item in the queue will require. Items are queued by copy, not by reference, so this is the number of bytes that will be copied for each posted item. Each item on the queue must be the same size.
pucQueueStorageBufferIf uxItemSize is not zero then pucQueueStorageBuffer must point to a uint8_t array that is at least large enough to hold the maximum number of items that can be in the queue at any one time - which is ( uxQueueLength * uxItemsSize ) bytes. If uxItemSize is zero then pucQueueStorageBuffer can be NULL.
pxQueueBufferMust point to a variable of type StaticQueue_t, which will be used to hold the queue's data structure.
If the queue is created then a handle to the created queue is returned. If pxQueueBuffer is NULL then NULL is returned.