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Chapter 6: IP Core Interfaces
6–11
Avalon-ST RX Interface
June 2012
Altera Corporation
Stratix V Hard IP for PCI Express
illustrates back-to-back transmission on the 64-bit Avalon-ST RX interface
with no idle cycles between the assertion of
rx_st_eop
and
rx_st_sop
.
Data Alignment and Timing for the 128-Bit Avalon-ST RX Interface
shows the mapping of 128-bit Avalon-ST RX packets to PCI Express TLPs
for TLPs with a three dword header and qword aligned addresses. The assertion of
rx_st_empty
in a
rx_st_eop
cycle, indicates valid data on the lower 64 bits of
rx_st_data
.
Figure 6–8. 64-Bit Avalon-ST Interface Back-to-Back Transmission
pld_clk
rx_st_data[63:0]
rx_st_sop
rx_st_eop
rx_st_ready
rx_st_valid
C.C. C. C. CCCC0089002...
C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C. C C
Figure 6–9. 128-Bit Avalon-ST rx_st_data
<n>
Cycle Definition for 3-Dword Header TLPs with Qword Aligned Addresses
pld_clk
rx_st_valid
rx_st_data[127:96]
rx_st_data[95:64]
rx_st_data[63:32]
rx_st_data[31:0]
rx_st_bardec[7:0]
rx_st_sop
rx_st_eop
rx_st_empty
data3
header2
data2
header1
data1
data<n>
header0
data0
data<n-1>
01