MDIO Leader IP Core

A Serial Bus Protocol to Configure the PHY Layer Transceiver Parameters

Management Data Input/Output (MDIO), or Media Independent Interface Management (MIIM) is a serial bus protocol defined for the IEEE 802.3 standard Ethernet series of Media Independent Interface (MII). MII connects media access control (MAC) devices to Ethernet physical layer (PHY) circuits. The SMI/MDIO protocol is a simple two-wire serial interface that connects the management unit to the managed PHY to control the PHY and capture the status of the PHY. registers provide status and control information such as: link status, speed ability and selection, power down for low power consumption, duplex mode (full or half), auto-negotiation, fault signaling, and loopback.

Bidirectional Shared Bus Structure - MDIO is a bidirectional shared bus structure that can provide a connection from the MAC (leader) up to 32 PHY (follower) devices.

Defined to meet the growing needs of 10 Gigabit Ethernet devices - MDIO was originally defined in Clause 22 of IEEE 802.3. To meet the growing needs of 10 Gigabit Ethernet devices, Clause 45 of the 802.3ae specification is introduced.


  • Three different standard interfaces for accessing the control and status signals of Leader: APB, AHB-L and AXI-L
  • User control for selection between Clause 22 and Clause 45 protocols
  • Dynamic selection for Preamble pattern generation in MDIO frames
  • User Control for clock divider settings for MDC clock

Block Diagram

Resource Utilization

Interface PFU registers LUT-4
AHB-L 145 190
APB 136 185
AXI-L 185 240


Quick Reference
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MDIO Leader IP Core - Lattice Radiant and Propel Software
FPGA-IPUG-02223 1.0 5/16/2023 PDF 1.7 MB

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