Note that all of the AXI channels follow the same rules:
• All TDATA and TUSER fields are packed in little endian format. That is, bit 0 of a sub-field is aligned to the same side as bit 0 of TDATA or TUSER.
• Fields are not included in TDATA or TUSER unless the core is configured in such a way that it needs the fields to be present. For example, if the core is configured to have a fixed-point size, no bits are allocated to the NFFT field that specifies the point size.
• All TDATA and TUSER vectors are multiples of 8 bits. When all fields in a TDATA or TUSER vector have been concatenated, the overall vector is padded to bring it up to an 8-bit boundary.