Altera Low Latency 40-Gbps Ethernet MAC and PHY MegaCore Function - Manual (Page 69)

Low Latency 40-100GbE IP Core RX Data Bus Without Adapters (Custom Streaming Interface)
The RX bus without adapters consists of four 8-byte words, or 256 bits, operating at a frequency of
390.625. for the 100GbE IP core or two 8-byte words, or 128 bits, for the 40GbE IP core, nominally at
312.5 MHz. This bus drives data from the RX MAC to the RX client.
Figure 3-17: RX MAC to Client Interface Without Adapters
The custom streaming interface bus width varies with the IP core variation. In the figure, = 2 for the
40GbE IP core and = 4 for the 100GbE IP core.
RX Client
Logic
RX MAC
dout_d[*64-1:0]
dout_c[*8-1:0]
dout_sop[-1:0]
dout_eop[-1:0]
dout_idle[-1:0]
dout_eop_empty[*3-1:0]
rx_fcs_error
rx_fcs_valid
rx_status[2:0]
dout_valid
clk_rxmac
rx_error[5:0]
Table 3-6: Signals of the RX Client Interface Without Adapters
In the table, = 2 for the 40GbE IP core and = 4 for the 100GbE IP core. The signals are clocked by
clk_rxmac
.
Signal Name Direction Description
dout_d[*64-
1:0]
Output Received data and Idle bytes. In RX preamble pass-through mode, this
bus also carries the preamble.
dout_c[*8-
1:0]
Output Indicates control bytes on the data bus. Each bit of dout_c indicates
whether the corresponding byte of
dout_d
is a control byte. A bit is
asserted high if the corresponding byte on
dout_d
is an Idle byte or the
Start byte, and has the value of zero if the corresponding byte is a data
byte or, in preamble pass-through mode, a preamble or SFD byte.
dout_sop[-
1:0]
Output Indicates the first data word of a frame, in the current
clk_rxmac
cycle.
In RX preamble pass-through mode, the first data word is the word
that contains the preamble. When the RX preamble pass-through
feature is turned off, the first data word is the first word of Ethernet
data that follows the preamble. This signal is one-hot encoded.
3-24 Low Latency 40-100GbE IP Core RX Data Bus Without Adapters (Custom Streaming
Interface)
UG-01172
2015.05.04
Altera Corporation Functional Description
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