Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs

ID 813652
Date 7/22/2024
Public
Document Table of Contents

4.6. Frame Status Checking

The IP checks the frame transmitted, frames received, and report the status information on the TX and RX interfaces:
Table 13.  TX Interface
Signal Direction Width Description
l2_txstatus_valid Out 1 When asserted, this signal qualifies l2_txstatus_data and l2_txstatus_error.
l2_txstatus_data Out 40

Contains information about the transmit frame.

  • Bits 0 to 15: Payload length
  • Bits 16 to 31: Frame length (from first byte of destination address to last byte of FCS)
  • Bit 32: Indicates a stacked VLAN frame
  • Bit 33: Indicates a VLAN frame.
  • Bit 34: Indicates a control frame.
  • Bit 35: Indicates a pause frame.
  • Bit 36: Indicates a broadcast frame.
  • Bit 37: Indicates a multicast frame.
  • Bit 38: Indicates a unicast frame.
  • Bit 39: Indicates a PFC frame.
l2_txstatus_error Out 7

When set to 1, the respective bit indicates the following error type in the transmit frame.

  • Bit 0: Unused
  • Bit 1: Oversized frame.
  • Bit 2: Payload length error
  • Bit 3 to 6: Unused
Table 14.  RX Interface
Signal Direction Width Description
l2_rxstatus_valid Out 1 When asserted, this signal qualifies l<x>_rxstatus_data.
l2_rxstatus_data Out 40

Contains information about the transmit frame.

  • Bits 0 to 15: Payload length
  • Bits 16 to 31: Frame length (from first byte of destination address to last byte of FCS)
  • Bit 32: Indicates a stacked VLAN frame
  • Bit 33: Indicates a VLAN frame.
  • Bit 34: Indicates a control frame.
  • Bit 35: Indicates a pause frame.
  • Bit 36: Indicates a broadcast frame.
  • Bit 37: Indicates a multicast frame.
  • Bit 38: Indicates a unicast frame.
  • Bit 39: Indicates a PFC frame.
l2_rxstatus_error Out  

Bit 0: PHY Error or malformed packet error.

  • Bit 1: CRC Error. The computed CRC value differs from the received CRC value.
  • Bit 2: Undersize error. The frame size is less than 64 bytes.
  • Bit 3: Oversize Error. The frame size is more than MAX_RX_SIZE_CONFIG register value.
  • Bit 4: Length Error. The actual frame payload length differs from the length/type field.
  • Bit 5: N/A.

This signal is aligned with rx_endofpacket.