Chapter 6: IP Core Interfaces
6–23
Avalon-ST TX Interface
November 2012
Altera Corporation
Arria V GZ Hard IP for PCI Express
Data Alignment and Timing for the 128-Bit Avalon-ST TX Interface
shows the mapping of 128-bit Avalon-ST TX packets to PCI Express TLPs
for a three dword header with qword aligned addresses. Assertion of
tx_st_empty
in
an
rx_st_eop
cycle indicates valid data in the lower 64 bits of
tx_st_data
.
shows the mapping of 128-bit Avalon-ST TX packets to PCI Express TLPs
for a 3 dword header with non-qword aligned addresses. It also shows
tx_st_err
assertion.
Figure 6–24. 128-Bit Avalon-ST tx_st_data Cycle Definition for 3-Dword Header TLP with Qword Aligned Address
Data3
Header2
Data 2
Header1
Data1
Data(n)
Header0
Data0
Data(n-1)
pld_clk
tx_st_valid
tx_st_data[127:96]
tx_st_data[95:64]
tx_st_data[63:32]
tx_st_data[31:0]
tx_st_sop
tx_st_eop
tx_st_empty
Figure 6–25. 128-Bit Avalon-ST tx_st_data Cycle Definition for 3-Dword Header TLP with non-Qword Aligned Address
pld_clk
tx_st_valid
tx_st_data[127:96]
tx_st_data[95:64]
tx_st_data[63:32]
tx_st_data[31:0]
tx_st_sop
tx_st_err
tx_st_eop
tx_st_empty
Data0
Data 4
Header 2
Data 3
Header 1
Data 2
Data (n)
Header 0
Data 1
Data (n-1)