GTS Ethernet Intel® FPGA Hard IP User Guide

ID 817676
Date 8/05/2024
Public

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4.5.2. Connect the MII PCS Mode RX Interface

The GTS Ethernet Intel® FPGA Hard IP RX client interface in PCS Only variations is MII.

Connect the RX MII interface, which is a source, to an MII compliant sink. Connect the interface as described in the table below, which illustrates how to transmit packets directly to the PCS RX interface.

Table 35.  MII RX Client Interface SignalsAll interface signals are clocked by the i_clk_rx. The signal names are standard Avalon® streaming interface signals.
Signal Name Width Description
o_rx_mii_d[63:0] 64 bits (10GE/25GE)
Receive Ethernet frames or MII control bytes, MII encoded, on this input data bus.
  • o_rx_mii_d[7:0] holds the first byte received on the Ethernet link.
  • o_rx_mii_d[0] holds the first bit received on the Ethernet link.
o_rx_mii_c[7:0] 8 bits (10GE/25GE)

Sample this bus to determine if o_rx_mii_d[63:0] input bus is carrying control or data bytes.

If the value of a bit is 1, the corresponding data byte is a control byte. If the value of a bit is 0, the corresponding data byte is data.

o_rx_mii_valid 1 bit

Sample this signal to qualify the RX MII data, RX MII control bits, and the RX valid alignment marker signals.

o_rx_mii_am_valid 1 bit

Sample this signal to determine if the IP core has received an alignment marker on the Ethernet link.

The following waveform shows how to receive packets from the RX PCS using the PCS mode RX interface.

Figure 40. Receiving Data on the PCS Mode RX Interface
  • The signal o_rx_mii_valid is driven high, qualifying that the data buses o_rx_mii_d and o_rx_mii_c are valid.
  • The bit order for the PCS mode RX interface is the same as the bit order of the client interface.
  • The first bit that the core receives is o_rx_mii_d[0].
Note: The PCS mode RX interface is not SOP aligned. Packets can begin on any byte position that is a multiple of 4 for 10GE/25GE.
Table 36.  Reading a Start Packet Block with Preamble from a PCS Mode TX Interface
MII Data MII Control Ethernet Packet Byte
o_rx_mii_d[7:0] 0xFB o_rx_mii_c[0] 1 Start of Packet
o_rx_mii_d[15:8] 0x55 o_rx_mii_c[1] 0 Preamble
o_rx_mii_d[23:16] 0x55 o_rx_mii_c[2] 0 Preamble
o_rx_mii_d[31:24] 0x55 o_rx_mii_c[3] 0 Preamble
o_rx_mii_d[39:32] 0x55 o_rx_mii_c[4] 0 Preamble
o_rx_mii_d[47:40] 0x55 o_rx_mii_c[5] 0 Preamble
o_rx_mii_d[55:48] 0x55 o_rx_mii_c[6] 0 Preamble
o_rx_mii_d[63:56] 0xD5 o_rx_mii_c[7] 0 SFD