3 network interface options, 4 fec frame transmission, Network interface options -46 – Freescale Semiconductor MCF5480 User Manual
Page 976: Fec frame transmission -46

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
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
.
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]