6–4
Chapter 6: IP Core Interfaces
Avalon-ST RX Interface
Arria V GZ Hard IP for PCI Express
November 2012
Altera Corporation
Avalon-ST RX Interface
describes the signals that comprise the Avalon-ST RX Datapath. The RX data
signal can be 64, 128, or 256 bits.
Table 6–3. 64-, 128-, or 256-Bit Avalon-ST RX Datapath (Part 1 of 4)
Signal
Width
Dir
Avalon-ST
Type
Description
rx_st_data
64,
128,
256
O
data
the mapping of the Transaction Layer’s TLP information to
rx_st_data
and examples of the timing of this interface. Note
that the position of the first payload dword depends on whether
the TLP address is qword aligned. The mapping of message
TLPs is the same as the mapping of TLPs with 4-dword
headers. When using a 64-bit Avalon-ST bus, the width of
rx_st_data
is 64. When using a 128-bit Avalon-ST bus, the
width of
rx_st_data
is 128. When using a 256-bit Avalon-ST
bus, the width of
rx_st_data
is 256 bits.
rx_st_sop
1,
2
O
start of
packet
Indicates that this is the first cycle of the TLP when
rx_st_valid
is asserted. When using a 256-bit Avalon-ST bus
the following correspondences apply:
When you turn on
Enable multiple packets per cycle
,
■
bit 0 indicates that a TLP begins in
rx_st_data[127:0]
■
bit 1 indicates that a TLP begins in
rx_st_data[255:128]
In single packet per cycle mode, this signal is a single bit which
indicates that a TLP begins in this cycle.
rx_st_eop
1, 2
O
end of
packet
Indicates that this is the last cycle of the TLP when
rx_st_valid
is asserted.
When using a 256-bit Avalon-ST bus the following
correspondences apply:
When you turn on
Enable multiple packets per cycle
,
■
bit 0 indicates that a TLP ends in
rx_st_data[127:0]
■
bit 1 indicates that a TLP ends in
rx_st_data[255:128]
In single packet per cycle mode, this signal is a single bit which
indicates that a TLP ends in this cycle.