Hard Processor System Technical Reference Manual: Agilex™ 3 SoCs

ID 848530
Date 6/23/2025
Public
Document Table of Contents

12.3.2.2.1. GMII Adapter

The multirate PHY GMII interface adapter module implements the 8 bit GMII interface to 16 bit IEEE 802.3.2005 standard GMII interface. This feature is required to interface the multirate PHY IP with HPS EMAC IP with 8 bit GMII interface. You can enable or disable this feature using the ENABLE_GMII_ADAPTER parameter.

The key changes in instantiating the core are as follows:
  • The adapter has one register bit called TX_DISABLE. This is absorbed in the MRPHY-GMII module and passed as signal to the adapter.
  • MRPHY_PLL generates 2.5 MHz, 25 MHz, and 125 MHz clocks for 10M, 100M, and 1G rates.
Figure 307. GMII8 Adapter

When you enabled the GMII adapter, ensure that the latency through this module is calculated and added along with the soft PCS latency number and update the respective registers.

Note: TX_DISABLE is "1" (asserted) by default. You must deassert TX_DISABLE for the adapter to enable TX traffic.