Chapter 6: IP Core Interfaces
6–21
Avalon-ST TX Interface
June 2012
Altera Corporation
Stratix V Hard IP for PCI Express
Data Alignment and Timing for the 64-Bit Avalon-ST TX Interface
illustrates the mapping between Avalon-ST TX packets and PCI Express
TLPs for three dword header TLPs with non-qword aligned addresses on a 64-bit bus.
(
Figure 6–2 on page 6–8
illustrates the storage of non-qword aligned data.)
Non-qword aligned address occur when
address[2]
is set. When address[2] is set,
tx_st_data[63:32]
contains
Data0
and
tx_st_data[31:0]
contains dword
header2
.
illustrates the mapping between Avalon-ST TX packets and PCI Express
TLPs for a four dword header with qword aligned addresses on a 64-bit bus.
Figure 6–19. 64-Bit Avalon-ST tx_st_data Cycle Definition for 3-Dword Header TLP with Non-Qword Aligned Address
Notes to
(1) Header0 ={pcie_hdr_byte0, pcie_hdr _byte1, pcie_hdr _byte2, pcie_hdr _byte3}
(2) Header1 = {pcie_hdr_byte4, pcie_hdr _byte5, header pcie_hdr byte6, pcie_hdr _byte7}
(3) Header2 = {pcie_hdr _byte8, pcie_hdr _byte9, pcie_hdr _byte10, pcie_hdr _byte11}
(4) Data0 = {pcie_data_byte3, pcie_data_byte2, pcie_data_byte1, pcie_data_byte0}
(5) Data1 = {pcie_data_byte7, pcie_data_byte6, pcie_data_byte5, pcie_data_byte4}
(6) Data2 = {pcie_data_byte11, pcie_data_byte10, pcie_data_byte9, pcie_data_byte8}
pld_clk
tx_st_data[63:32]
tx_st_data[31:0]
tx_st_sop
tx_st_eop
Header1
Data0
Data2
Header0
Header2
Data1
Figure 6–20. 64-Bit Avalon-ST tx_st_data Cycle Definition for 4-Dword TLP with Qword Aligned Address
Notes to
(1) Header0 = {pcie_hdr_byte0, pcie_hdr _byte1, pcie_hdr _byte2, pcie_hdr _byte3}
(2) Header1 = {pcie_hdr _byte4, pcie_hdr _byte5, pcie_hdr byte6, pcie_hdr _byte7}
(3) Header2 = {pcie_hdr _byte8, pcie_hdr _byte9, pcie_hdr _byte10, pcie_hdr _byte11}
(4) Header3 = pcie_hdr _byte12, pcie_hdr _byte13, header_byte14, pcie_hdr _byte15}, 4 dword header only
(5) Data0 = {pcie_data_byte3, pcie_data_byte2, pcie_data_byte1, pcie_data_byte0}
(6) Data1 = {pcie_data_byte7, pcie_data_byte6, pcie_data_byte5, pcie_data_byte4}
pld_clk
tx_st_data[63:32]
tx_st_data[31:0]
tx_st_sop
tx_st_eop
Header1
Header3
Data1
Header0
Header2
Data0