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Table 19: Sideband Signals in pcie(n)_s_axis_rq_tuser (512-bit Interface)
Bit Index
Name
Width
Description
7:0
first_be[7:0]
8
Byte enables for the first Dword. This field must be set
based on the desired value of the first_be bits in the
Transaction-Layer header of the request TLP. first_be[3:0]
corresponds to the byte enables for the first TLP starting in
this beat, and first_be[7:4] corresponds to the byte enables
for the second TLP starting in this beat (if present).
For Memory Reads, I/O Reads and Configuration Reads,
these 4 bits indicate the valid bytes to be read in the first
Dword. For Memory Writes, I/O Writes and Configuration
Writes, these bits indicate the valid bytes in the first Dword
of the payload.
The core samples this field in the first beat of a packet,
when pcie(n)_s_axis_rq_tvalid and pcie(n)_s_axis_rq_tready
are both High.
15:8
last_be[7:0]
8
Byte enables for the last Dword.
This field must be set based on the desired value of the
last_be bits in the Transaction-Layer header of the TLP.
last_be[3:0] corresponds to the byte enables for the first TLP
starting in this beat, and last_be[7:4] corresponds to the
byte enables for the second TLP starting in this beat (if
present).
For Memory Reads and Writes of one DW transfers and zero
length transfers, these bits should be 0s.
For Memory Reads of 2 Dwords or more, these 4 bits
indicate the valid bytes to be read in the last Dword of the
block of data. For Memory Writes of 2 Dwords or more,
these bits indicate the valid bytes in the last Dword of the
payload.
The core samples this field in the first beat of a packet,
when pcie(n)_s_axis_rq_tvalid and pcie(n)_s_axis_rq_tready
are both High.
19:16
addr_offset[3:0]
4
When 128b the address-aligned mode is in use on this
interface, the user application must provide the offset
where the payload data begins (in multiples of 4 bytes) on
the data bus on this sideband bus. This enables the core to
determine the alignment of the data block being
transferred.
addr_offset[1:0] corresponds to the offset for the first TLP
starting in this beat, and addr_offset[3:2] is reserved for
future use.
The core samples this field in the first beat of a packet,
when pcie(n)_s_axis_rq_tvalid and pcie(n)_s_axis_rq_tready
are both High.
When the requester request interface is configured in the
Dword-alignment mode, these bits must always be set to 0.
Chapter 3: Product Specification
PG346 (v3.3) November 16, 2022
CPM Mode for PCI Express
64