Freescale Semiconductor MCF5480 - Manual (Page 976)

MCF548x Reference Manual, Rev. 3
30-46 Freescale Semiconductor
30.4.3 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), the following 12 signals are defined by the IEEE 802.3 standard and supported
by the FEC. These signals are shown in Table 30-47 below.
The 7-wire serial mode interface (RCR[MII_MODE] = 0) operates in what is generally referred to as the
“AMD” mode. The 7-wire mode connections to the external transceiver are shown in Table 30-48 .
30.4.4 FEC Frame Transmission
The Ethernet transmitter is designed to work with almost no intervention from software. Once
ECR[ETHER_EN] is set and data appears in the transmit FIFO, the FEC is able to transmit onto the
network.
Table 30-47. MII Mode
Signal Description EMAC Supported Signal
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
Input/Output
EMDIO
Table 30-48. 7-Wire Mode Configuration
Signal Description EMAC Supported Signal
Transmit Clock ETXCLK
Transmit Enable ETXEN
Transmit Data ETXD[0]
Collision ECOL
Receive Clock ERXCLK
Receive Data Valid ERXDV
Receive Data ERXD[0]