4.4.1. TLP Header and Data Alignment for the Avalon-ST RX and TX Interfaces
The TLP prefix, header and data are sent and received on the TX and RX interfaces.
The ordering of bytes in the header and data portions of packets is different. The first byte of the header dword is located in the most significant byte of the dword. The first byte of the data dword is located in the least significant byte of the dword on the data bus.