7.3.1. RX MAC Avalon ST Client Interface with Disabled Preamble Passthrough - 2026-01-06

F-Tile Ethernet Hard IP User Guide
Version
25.1.1
Table 41.  RX MAC Field Positions in o_rx_data with Preamble Passthrough Disabled
100GE

o_rx_data

 40GE/50GE

o_rx_data

 10GE/25GE

o_rx_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]  
[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] [47:40] [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] …
In the table above, the byte order on the bus and the data bit order follow the TX MAC Avalon ST client interface. For example,
  • For 100GE, the first received bit after the SFD was bit 504, i.e. bit 0 of the first received byte.
  • For 40GE/50GE, the first bit of the first received byte is bit 120.
  • For 10GE/25GE, the first bit of the first received byte that is bit 56.