# MDIO

## Modules

| MDIO Symbols Defined
| MDIO Data Structures
| MDIO Functions
| MDIO Enumerated Data Types

## Detailed Description

## Introduction

### Overview

The Management Data Input/Output (MDIO) module manages up to 32 physical layer (PHY) devices connected to the Ethernet Media Access Controller (EMAC). The MDIO module allows almost transparent operation of the MDIO interface with little maintenance from the CPU. The MDIO module enumerates all PHY devices in the system by continuously polling 32 MDIO addresses. Once it detects a PHY device, the MDIO module reads the PHY status register to monitor the PHY link state. The MDIO module stores link change events that can interrupt the CPU. The event storage allows the CPU to poll the link status of the PHY device without continuously performing MDIO module accesses. However, when the system must access the MDIO module for configuration and negotiation, the MDIO module performs the MDIO read or write operation independent of the CPU. This independent operation allows the DSP to poll for completion or interrupt the CPU once the operation has completed.

### References

1. EMAC/MDIO User's Guide SPRUFC4.pdf (May 2008)

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