F-Tile Ethernet Intel® FPGA Hard IP User Guide

ID 683023
Date 6/26/2023
Public

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7.2.1. TX MAC Avalon ST Client Interface with Disabled Preamble Passthrough

Figure 35. Fields and Frame Boundaries in an Ethernet PacketWhen you turn off Preamble Passthrough in the parameter editor, i_tx_data must be written as shown below for the first cycle of data presented to the MAC.
Note: For 10GE/25GE channels, multiple cycles are required to write the header data.
Table 36.  TX MAC Field Positions in i_tx_data with Preamble Passthrough Disabled
Attention:

10GE/25GE requires multiple transfer cycle for header data.

The (') symbol in the 10GE/25GE i_tx_data column represents transfer on the subsequent cycle.

100GE

i_tx_data

40GE/50GE

i_tx_data

10GE/25GE

i_tx_data

MAC Field Note
[511:504] [127:120] [63:56]' Dest Addr[47:40] The first octet of the Destination Address, follows Start Frame Delimiter (SFD).
[503:496] [119:112] [55:48]' Dest Addr[39:32]
[495:488] [111:104] [47:40]' Dest Addr[31:24]  
[495:480] [103:96] [39:32]' Dest Addr[23:16]  
[479:472] [95:88] [31:24]' Dest Addr[15:8]  
[471:464] [87:80] [23:16]' Dest Addr[7:0]  
[463:456] [79:72] [15:8]' Src Addr[47:40] When you turn on Source Address Insertion, contents are replaced by txmac_saddr unless i_tx_skip_crc is high.
[455:448] [71:64] [7:0]' Src Addr[39:32]
[447:440] [63:56] [63:56] Src Addr[31:24]
[439:432] [55:48] [55:48] Src Addr[23:16]
[431:424] [39:32] [47:40] Src Addr[15:8]
[423:416] [39:32] [39:32] Src Addr[7:0]
[415:408] [31:24] [31:24] Length/Type[15:8]
[407:400] [23:16] [23:16] Length/Type[7:0]
[399:0] [15:0] [15:0]
Note:
  • In the table above, the byte order on the bus flows from MSB to LSB, the first byte of the MAC destination address is the MSB. The MAC considers this to be the first byte after the Start Frame Delimiter (SFD).
  • The bit numbered 0 is always the least significant bit of each byte.
    • For example, on 100GE interface, i_tx_data[504] transmits after the SFD, and corresponds to the Ethernet destination address unicast/multicast bit.