* 1) RX Free Fifo - RXF - holds descriptors of empty buffers to accept incoming
* traffic. This Fifo is filled by SW and is readen by HW. Each descriptor holds
* info about buffer's location, size and ID. An ID field is used to identify a
* 1) RX Free Fifo - RXF - holds descriptors of empty buffers to accept incoming
* traffic. This Fifo is filled by SW and is readen by HW. Each descriptor holds
* info about buffer's location, size and ID. An ID field is used to identify a