F-Tile Ethernet Intel® FPGA Hard IP User Guide

ID 683023
Date 10/04/2021
Public

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7.4.2. TX MAC Segmented Client Interface with Enabled Preamble Passthrough

When you turn on Preamble Passthrough in the parameter editor, you must provide 8 preamble bytes to the TX MAC segmented client interface.
The table below describes TX MAC segmented field positions with enabled Preamble Passthrough parameter.
  • MII Start of Packet control byte always replaces the first preamble byte.
  • Bits[55:8] are the preamble bits, typically set to the 0x55 value.
  • Bits[63:56] are the last preamble byte. In a standard preamble, it is set to the Start Frame Delimeter 0xD5 value.
Table 40.  TX MAC Segmented Field Positions in i_tx_mac_data with Preamble Passthrough Enabled
Attention:

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

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

The ('') symbol in the 10GE/25GE i_tx_mac_data column represents transfer on the 2nd subsequent cycle.

100GE/400GE

i_tx_mac_data

40GE/50GE

i_tx_mac_data

10GE/25GE

i_tx_mac_data

MAC Field Note
[7:0] [7:0]' [7:0]'' Custom Preamble [7:0] MII SOP control channel replaces it.
[15:8] [15:8]' [15:8]'' Custom Preamble [15:8] 0x55
[23:16] [23:16]' [23:16]'' Custom Preamble [23:16] 0x55
[31:24] [31:24]' [31:24]'' Custom Preamble [31:24] 0x55
[39:32] [39:32]' [39:32]'' Custom Preamble [39:32] 0x55
[47:40] [47:40]' [47:40]'' Custom Preamble [47:40] 0x55
[55:48] [55:48]' [55:48]'' Custom Preamble [55:48] 0x55
[63:56] [63:56]' [63:56]'' Custom Preamble [63:56] 0xD5 (SFD)
[71:64] [71:64]' [7:0]' Dest Addr[47:40]  
[79:72] [79:72]' [15:8]' Dest Addr[39:32]  
[87:80] [87:80]' [23:16]' Dest Addr[31:24]  
[95:88] [95:88]' [31:24]' Dest Addr[23:16]  
[103:96] [103:96]' [39:32]' Dest Addr[15:8]  
[111:104] [111:104]' [47:40]' Dest Addr[7:0]  
[119:112] [119:112]' [55:48]' Src Addr[47:40] When you turn on Source Address Insertion, contents are replaced by txmac_saddr unless i_tx_skip_crc is high.
[127:120] [127:120]' [63:56]' Src Addr[39:32]
[135:128] [7:0] [7:0] Src Addr[31:24]
[143:136] [15:8] [15:8] Src Addr[23:16]
[151:144] [23:16] [23:16] Src Addr[15:8]
[159:152] [31:24] [31:24] Src Addr[7:0]
[167:160] [39:32] [39:32] Length/Type[15:8]
[175:168] [47:40] [47:40] Length/Type[7:0]
[…:176] [127:48] [63:48]