Low Latency Ethernet 10G MAC Intel® Cyclone® 10 GX FPGA IP Design Example User Guide

ID 683354
Date 11/30/2020
Public
Document Table of Contents

4.3. Avalon® Streaming Interface Signals

Table 12.   Avalon® Streaming Interface Signals
Signal Direction Width Description
avalon_st_tx_startofpacket[] In [NUM_CHANNELS] Assert this signal to indicate the beginning of the TX data.
avalon_st_tx_endofpacket[] In [NUM_CHANNELS] Assert this signal to indicate the end of the TX data.
avalon_st_tx_valid[] In [NUM_CHANNELS] Assert this signal to indicate that avalon_st_tx_data[] and other signals on this interface are valid.
avalon_st_tx_ready[] Out [NUM_CHANNELS] When asserted, indicates that the MAC IP core is ready to accept data. The reset value of this signal is non-deterministic.
avalon_st_tx_error[] In [NUM_CHANNELS] Assert this signal to indicate that the current TX packet contains errors.
avalon_st_tx_data[][] In [NUM_CHANNELS][m]

TX data from the client.

m is 64 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 32.

avalon_st_tx_empty[][] In [NUM_CHANNELS][m]

Use this signal to specify the number of empty bytes in the cycle that contain the end of the TX data.

m is 3 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 2.

  • 0x0—All bytes are valid.
  • 0x1—The last byte is invalid.
  • 0x2—The last two bytes are invalid.
  • 0x3—The last three bytes are invalid.
avalon_st_rx_startofpacket[] Out [NUM_CHANNELS] When asserted, indicates the beginning of the RX data.
avalon_st_rx_endofpacket[] Out [NUM_CHANNELS] When asserted, indicates the end of the RX data.
avalon_st_rx_valid[] Out [NUM_CHANNELS] When asserted, indicates that the avalon_st_rx_ data[] signal and other signals on this interface are valid.
avalon_st_rx_ready[] In [NUM_CHANNELS] Assert this signal when the client is ready to accept data.
avalon_st_rx_error[][] Out [NUM_CHANNELS][6] When set to 1, the respective bits indicate an error type:
  • Bit 0—PHY error. For 10 Gbps, the data on xgmii_rx_data contains a control error character (FE). For 10 Mbps,100 Mbps,1 Gbps, gmii_rx_err or mii_rx_err is asserted.
  • Bit 1—CRC error. The computed CRC value differs from the received CRC.
  • Bit 2—Undersized frame. The receive frame length is less than 64 bytes.
  • Bit 3—Oversized frame. The receive frame length is more than MAX_FRAME_SIZE.
  • Bit 4—Payload length error. The actual frame payload length is different from the value in the length/type field.
  • Bit 5—Overflow error. The receive FIFO buffer is full while it is still receiving data from the MAC IP core.
avalon_st_rx_data[][] Out [NUM_CHANNELS][m]

RX data to the client.

m is 64 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 32.

avalon_st_rx_empty[][] Out [NUM_CHANNELS][m]

Contains the number of empty bytes during the cycle that contain the end of the RX data.

m is 3 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 2.

avalon_st_tx_status_valid[] Out [NUM_CHANNELS] When asserted, this signal qualifies the avalon_st_txstatus_data[] and avalon_st_txstatus_error[] signals.
avalon_st_tx_status_data[][] Out [NUM_CHANNELS][40] Contains information about the TX frame.
  • Bits 0 to 15—Payload length.
  • Bits 16 to 31—Packet length.
  • Bit 32—When set to 1, indicates a stacked VLAN frame.
  • Bit 33—When set to 1, indicates a VLAN frame.
  • Bit 34—When set to 1, indicates a control frame.
  • Bit 35—When set to 1, indicates a pause frame.
  • Bit 36—When set to 1, indicates a broadcast frame.
  • Bit 37—When set to 1, indicates a multicast frame.
  • Bit 38—When set to 1, indicates a unicast frame.
  • Bit 39—When set to 1, indicates a PFC frame.
avalon_st_tx_status_error[][] Out [NUM_CHANNELS][7] When set to 1, the respective bit indicates the following error type in the RX frame.
  • Bit 0—Undersized frame.
  • Bit 1—Oversized frame.
  • Bit 2—Payload length error.
  • Bit 3—Unused.
  • Bit 4—Underflow.
  • Bit 5—Client error.
  • Bit 6—Unused.
The error status is invalid when an overflow occurs.
avalon_st_rxstatus_valid[] Out [NUM_CHANNELS]

When asserted, this signal qualifies the avalon_st_rxstatus_data[] and avalon_st_rxstatus_error[] signals.

The MAC IP core asserts this signal in the same clock cycle the avalon_st_rx_endofpacket signal is asserted.

avalon_st_rxstatus_data[][] Out [NUM_CHANNELS][40] Contains information about the RX frame.
  • Bits 0 to 15—Payload length.
  • Bits 16 to 31—Packet length.
  • Bit 32—When set to 1, indicates a stacked VLAN frame.
  • Bit 33—When set to 1, indicates a VLAN frame.
  • Bit 34—When set to 1, indicates a control frame.
  • Bit 35—When set to 1, indicates a pause frame.
  • Bit 36—When set to 1, indicates a broadcast frame.
  • Bit 37—When set to 1, indicates a multicast frame.
  • Bit 38—When set to 1, indicates a unicast frame.
  • Bit 39—When set to 1, indicates a PFC frame.
avalon_st_rxstatus_error[][] Out [NUM_CHANNELS][7] When set to 1, the respective bit indicates the following error type in the RX frame.
  • Bit 0—Undersized frame.
  • Bit 1—Oversized frame.
  • Bit 2—Payload length error.
  • Bit 3—Unused.
  • Bit 4—Underflow.
  • Bit 5—Client error.
  • Bit 6—Unused.
The error status is invalid when an overflow occurs.
avalon_st_pause_data[][] In [NUM_CHANNELS][2] This signal takes effect when the register bits, tx_pauseframe_enable[2:1], are both set to the default value 0.

Set this signal to the following values to trigger the corresponding actions.

  • 0x0—Stops pause frame generation.
  • 0x1—Generates an XON pause frame.
  • 0x2—Generates an XOFF pause frame. The MAC IP core sets the pause quanta field in the pause frame to the value in the tx_pauseframe_quanta register.
  • 0x3—Reserved.

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