Sending a write tlp, Sending a write tlp -27 – Altera Arria 10 Avalon-MM User Manual
Page 93
Figure 6-11: Layout of Data with 4 Dword Headers
Header 1 [63:32]
Cycle 1
Data Unaligned to
QWord Boundary
Data Aligned to
QWord Boundary
Cycle 2
Header 0 [31:0]
Header 3[63:32]
Header 2 [31:0]
Data [63:32]
Header 1 [63:32]
Header 0 [31:0]
Header 2 [31:0]
Cycle 1
Cycle 2
Cycle 3
Cycle 3
Data [31:0]
Unused, but must
be written
Unused, but must
be written
Header 3[63:32]
Register 1
Register 0
Register 1
Register 0
Register 1
Register 0
Register 1
Register 0
Register 1
Register 0
Register 1
Register 0
The TX TLP programming model scales with the data width. The Application Layer performs the same
writes for both the 64- and 128-bit interfaces. The Application Layer can only have one outstanding non-
posted request at a time. The Application Layer must use tags 16–31 to identify non-posted requests.
Note: For Root Ports, the Avalon-MM bridge does not filter Type 0 Configuration Requests by device
number. Application Layer software should filter out all requests to Avalon-MM Root Port
registers that are not for device 0. Application Layer software should return an Unsupported
Request Completion Status.
Sending a Write TLP
The Application Layer performs the following sequence of Avalon-MM accesses to the CRA slave port to
send a Memory Write Request:
1. Write the first 32 bits of the TX TLP to
RP_TX_REG0.
2. Write the next 32 bits of the TX TLP to
RP_TX_REG1.
3. Write the
RP_TX_CNTRL.SOP
to 1’b1 to push the first two dwords of the TLP into the Root Port TX
FIFO.
4. Repeat Steps 1 and 2. The second write to
RP_TX_REG1
is required, even for three dword TLPs with
aligned data.
5. If the packet is complete, write
RP_TX_CNTRL
to 2’b10 to indicate the end of the packet. If the packet is
not complete, write 2’b00 to
RP_TX_CNTRL.
6. Repeat this sequence to program a complete TLP.
When the programming of the TX TLP is complete, the Avalon-MM bridge schedules the TLP with
higher priority than TX TLPs coming from the TX slave port.
UG-01145_avmm
2015.05.14
Sending a Write TLP
6-27
Registers
Altera Corporation