Providing the Command Field Out-of-Band - 7.2 English

AXI 1G/2.5G Ethernet Subsystem Product Guide (PG138)

Document ID
PG138
Release Date
2023-11-15
Version
7.2 English

When not electing to provide the Command Field In-line with the frame sent for transmission, it must instead be provided out-of-band. This is achieved by expanding the size of the signal from that already defined in the current AXI4-Stream Interface – Transmit (see the Tri-Mode Ethernet MAC LogiCORE IP Product Guide (PG051).

Selecting this mode is through an AXI4-Lite addressable configuration bit (see the following table).

The signal definition for this expanded tx_axis_tuser is defined in the following table. A timing diagram showing the operation of this signal for normal frame transmission follows the following table. To summarize, the Command Field bits of tx_axis_tuser must be valid on the same clock cycle when the first data word of the frame is sent for transmission.

Table 1. tx_axis_tuser Bit Field Definition
Bits Name Description
tx_axis_tuser [0] Underrun AXI4-Stream user signal used to signal explicit underrun. This is defined in the 1G/2.5G Ethernet PCS/PMA or SGMII LogiCORE IP Product Guide (PG047) and Tri-Mode Ethernet MAC LogiCORE IP Product Guide (PG051).
tx_axis_tuser[63:1] Reserved Reserved for future use (all bits are ignored).
tx_axis_tuser[127:64] Command Field

A 64-bit field as per the Command Field definition of Table 1. This field is only valid when you have elected not to use the In-Line option of Providing the Command Field In-Line.

(Otherwise, all of these bits are ignored).

Figure 1. AXI4-Stream Interface Timing – Out-of-Band Command Field AXI Ethernet Page-1 Sheet.1 Sheet.2 Sheet.3 Sheet.4 Sheet.5 Sheet.6 Sheet.7 Sheet.8 Sheet.9 Sheet.10 Sheet.11 Sheet.12 Sheet.13 Sheet.14 Sheet.15 Sheet.16 tx_mac_clk tx_mac_clk Sheet.17 Sheet.18 Sheet.19 Sheet.20 Sheet.21 Sheet.22 1st data word 1st data word Sheet.23 Sheet.24 Sheet.25 Sheet.26 Sheet.27 Sheet.28 Sheet.29 Sheet.30 tx_axis_tdata tx_axis_tdata Sheet.31 Sheet.32 Sheet.33 Sheet.34 Sheet.35 Sheet.36 Sheet.37 tx_axis_tvalid tx_axis_tvalid Sheet.38 tx_axis_tready tx_axis_tready Sheet.39 Sheet.40 Sheet.41 Sheet.42 Sheet.43 Sheet.44 Sheet.45 Sheet.46 Sheet.47 Sheet.48 Sheet.49 COMMAND/TAG COMMAND/TAG Sheet.50 Sheet.51 Sheet.52 Sheet.53 Sheet.54 Sheet.55 tx_axis_tuser[127:64] tx_axis_tuser[127:64] Sheet.56 Sheet.57 Sheet.58 Sheet.59 Sheet.60 Sheet.61 Sheet.62 tx_axis_tlast tx_axis_tlast Sheet.63 Sheet.64 X15631-100818 X15631-100818