# EMAC

## Modules

| EMAC Symbols Defined
| EMAC Data Structures
| EMAC Functions

## Detailed Description

## Introduction

### Overview

The Ethernet Media Access Controller (EMAC) module provides an interface between the C6457 DSP core processor and the networked community. The EMAC supports 10Base-T (10 Mbits/second [Mbps]), and 100BaseTX (100 Mbps), in either half- or full-duplex mode, and 1000BaseT (1000 Mbps) in full-duplex mode, with hardware flow control and quality-of-service (QOS) support. There are two ports of EMAC on C6457 DSP. The EMAC module conforms to the IEEE 802.3-2002 standard, describing the "Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer" specifications. The IEEE 802.3 standard has also been adopted by ISO/IEC and re-designated as ISO/IEC 8802-3:2000(E). Deviation from this standard, the EMAC module does not use the Transmit Coding Error signal MTXER. Instead of driving the error pin when an underflow condition occurs on a transmitted frame, the EMAC will intentionally generate an incorrect checksum by inverting the frame CRC, so that the transmitted frame will be detected as an error by the network.

The EMAC control module is the main interface between the device core processor, the MDIO module, and the EMAC module. The EMAC control module contains the necessary components to allow the EMAC to make efficient use of device memory, plus it controls device interrupts. The EMAC control module incorporates 8K-bytes of internal RAM to hold EMAC buffer descriptors.

### References

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

### Assumptions

The abbreviations EMAC, emac and Emac have been used throughout this document to refer to Ethernet Media Access Controller and MDIO or mdio or Mdio refer to Management Data Input/Output.

Copyright 2012, Texas Instruments Incorporated