40- and 100-Gbps Ethernet MAC and PHY MegaCore Function User Guide

ID 683114
Date 6/15/2022
Public
Document Table of Contents

3.2.2.3. 40-100GbE IP Core TX Data Bus Without Adapters (Custom Streaming Interface)

When no adapters are used, the 40GbE custom interface bus width is 2 words (128 bits) and the 100GbE custom interface bus width is 5 words (320 bits). In both cases the client interfaces operate at a frequency above 315 MHz.

Figure 14. TX Client to MAC 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> = 5 for the 100GbE IP core.
Table 20.  Signals of the TX Client Interface Without Adapters In the table, <w> = 2 for the 40GbE IP core and <w> = 5 for the 100GbE IP core.

Signal Name

Direction

Description

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

Input

Data bytes to send in big-Endian mode.

din_start[<w>-1:0]

Input

Start of packet (SOP) location in the TX data bus. Only the most significant byte of each 64‑bit word may be a start of packet. Bit 63 or 127 are possible for the 40GbE and bits 319, 255, 191, 127, or 63 are possible for 100 GbE.

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

Input

End of packet. Any byte may be the last byte in a packet.

din_ack

Output

Indicates that input data was accepted by the IP core.

clk_txmac

Input

TX MAC clock. The minimum clock frequency is 315 MHz for the circuit to function correctly. The clk_txmac and clk_rxmac which clocks the RX datapath are not related and their rates do not have to match.

The IP core reads the bytes in big endian order. A packet may start in the most significant byte of any word. A packet may end on any byte.

To avoid sending packets before the IP core completes the reset sequence, you should ensure that the application does not send packets on the TX client interface until after the lanes_deskewed signal is asserted.