Triple-Speed Ethernet IP User Guide: Agilex™ 3 and Agilex™ 5 FPGAs and SoCs

ID 813669
Date 8/04/2025
Public
Document Table of Contents

10.2.3. Packet Drop

MAC drops packet at TX (packet is observed at Avalon® streaming interface IF but not at MII/GMII/RGMII IF) and RX (packet is observed at MII/GMII/RGMII IF, not at Avalon® streaming interface IF).
  1. Read command_config register and ensure that MAC TX_ENA and RX_ENA bits are set to 1.
  2. Ensure MAC is not in software reset state.
  3. For RX path, make sure MII/GMII/RGMII packets are the correct Ethernet format.
Note:

[1] Before the 10th packet transmit, the tx_ena bit is not enabled which causes the 10th packet being discarded.

[2] The purpose of writing to 0x015A and 0x015B in the command_config register during data transmit is to disable and enable the tx_ena bit in this register in order to enable and disable the TX channel. This causes the tx_ready to go to zero. If the tx_ready is zero for a number of cycles, the SUA (service unavailable) is asserted. In this instance, a tx_eop and tx_error is asserted and the packet is discarded by the IP.