mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 228

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

FEC Frame Transmission
The serial mode interface operates in what is generally referred to as AMD mode. The
MCF5272 configuration for seven-wire serial mode connections to the external transceiver
are shown in Table 11-2.
11.4 FEC Frame Transmission
Figure 11-3 shows the Ethernet frame format.
The Ethernet transmitter is designed to work with almost no host intervention. As soon as
the driver enables the FEC transmitter by setting ECR[ETHER_EN] and TDAR[24], the
FEC fetches the first transmit buffer descriptor (TxBD). If the user has a frame ready to
11-4
Preamble
7 Bytes
NOTE: Short Tx frames are padded automatically by the MCF5272
Start Frame
Delimiter
1 Byte
Transmit clock
Transmit enable
Transmit data
Collision
Receive clock
Receive enable
Receive data
Unused, configure as PB14
Unused input, tie to ground
Unused, configure as PB[13:11]
Unused output, ignore
Unused, configure as PB[10:8]
Unused, configure as PB15
Input after reset, connect to ground
Management channel clock
Management channel serial data
Table 11-2. Seven-Wire Mode Configuration
Figure 11-3. Ethernet Frame Format
Destination
Address
6 Bytes
Table 11-1. MII Mode (Continued)
Signal Description
Signal Description
MCF5272 User’s Manual
Address
6 Bytes
Source
Stored in T ransmit Buffer
Stored in Receive Buffer
2 Bytes
Length
T ype/
MCF5272 Pin
E_TxCLK
E_TxEN
E_TxD[0]
E_COL
E_RxCLK
E_RxDV
E_RxD[0]
E_RxER
E_CRS
E_RxD[3:1]
E_TxER
E_TxD[3:1]
E_MDC
E_MDIO
E_MDIO
MCF5272 Pin
E_MDC
46–1500 Bytes
Data
(Pads)
Frame Check
Sequence
4 Bytes
MOTOROLA