Functional Description

17.4.5 Network Interface Options

The FEC supports both an MII interface for 10/100 Mbps Ethernet and a 7-wire serial interface for 10 Mbps Ethernet. The interface mode is selected by the RCR[MII_MODE] bit. In MII mode (RCR[MII_MODE] = 1), there are 18 signals defined by the IEEE 802.3 standard and supported by the EMAC. These signals are shown in Table 17-5below.

Table 17-5. MII Mode

Signal Description

EMAC pin

 

 

Transmit Clock

ETXCLK

 

 

Transmit Enable

ETXEN

 

 

Transmit Data

ETXD[3:0]

 

 

Transmit Error

ETXER

 

 

Collision

ECOL

 

 

Carrier Sense

ECRS

 

 

Receive Clock

ERXCLK

 

 

Receive Data Valid

ERXDV

 

 

Receive Data

ERXD[3:0]

 

 

Receive Error

ERXER

 

 

Management Data Clock

EMDC

 

 

Management Data

EMDIO

Input/Output

 

 

 

The 7-wire serial mode interface (RCR[MII_MODE] = 0) operates in what is generally referred to as the “AMD” mode. 7-wire mode connections to the external transceiver are shown in Table 17-6.

Table 17-6. 7-Wire Mode Configuration

SIGNAL DESCRIPTION

EMAC PIN

 

 

Transmit Clock

ETXCLK

 

 

 

Transmit Enable

ETXEN

 

 

 

Transmit Data

ETXD[0]

 

 

 

Collision

ECOL

 

 

 

Receive Clock

ERXCLK

 

 

 

Receive Data Valid

ERXDV

 

 

 

Receive Data

ERXD[0]

 

 

 

17-8

MCF5282 User’s Manual

MOTOROLA

Page 364
Image 364
Motorola MCF5282, MCF5281 Network Interface Options, MII Mode, Wire Mode Configuration, Signal Description Emac pin