Avalon‑st rx interface – Altera Stratix V Avalon-ST User Manual
Page 40
Signal
Direction
Description
tx_cred_hdrfccp[7:0]
Output
Header credit limit for the FC completions. Each credit is 20
bytes.
tx_cred_hdrfcnp[7:0]
Output
Header limit for the non-posted requests. Each credit is 20 bytes.
tx_cred_hdrfcp[7:0]
Output
Header credit limit for the FC posted writes. Each credit is 20
bytes.
Avalon‑ST RX Interface
Table 4-3: 128- or 256‑Bit Avalon-ST RX Datapath
Signal
Direction
Description
rx_st_data[
Output
Receive data bus. Refer to figures following this table for 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 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
Output
Indicates that this is the first cycle of the TLP when
rx_st_valid
is asserted.
rx_st_eop
Output
Indicates that this is the last cycle of the TLP when
rx_st_valid
is asserted.
rx_st_empty[1:0]
Output
Indicates the number of empty qwords in
rx_st_data
. Valid
only when
rx_st_eop
is asserted in 128-bit and 256-bit modes.
For 128-bit data, only bit 0 applies; this bit indicates whether the
upper qword contains data. For 256-bit data single packet per
cycle mode, both bits are used to indicate whether 0-3 upper
UG-01097_sriov
2014.12.15
Avalon‑ST RX Interface
4-5
Interfaces and Signal Descriptions
Altera Corporation