Altera Low Latency 40-Gbps Ethernet MAC and PHY MegaCore Bedienungsanleitung PDF herunterladen (Seite 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, <w> = 2 for the

40GbE IP core and <w> = 4 for the 100GbE IP core.

RX Client

Logic

RX MAC

dout_d[<w>*64-1:0]

dout_c[<w>*8-1:0]

dout_sop[<w>-1:0]

dout_eop[<w>-1:0]

dout_idle[<w>-1:0]

dout_eop_empty[<w>*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, <w> = 2 for the 40GbE IP core and <w> = 4 for the 100GbE IP core. The signals are clocked by

clk_rxmac.

Signal Name Direction Description

dout_d[<w>*64-

1:0]

Output Received data and Idle bytes. In RX preamble pass-through mode, this

bus also carries the preamble.

dout_c[<w>*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[<w>-

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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