Chapter 11. Ethernet Module
11-3
Transceiver Connection
The descriptor controller manages data flow in both transmit and receive directions. It is
programmed with microcode to open and close buffer descriptors, control the transmit
collision recovery process, and filter received frame addresses.
The descriptor controller accesses both the transmit and receive descriptor rings through the
descriptor access block. The descriptor access block acts as a dedicated single channel
DMA that either reads a descriptor in external user memory or writes an updated descriptor
back into user memory.
11.3 Transceiver Connection
The FEC supports both an MII interface for 10/100 Mbps Ethernet and a seven-wire serial
interface for 10 Mbps Ethernet. The interface mode is selected by
R_CNTRL[MII_MODE]. In MII mode, the 802.3 standard defines and the FEC module
supports 18 signals. These are shown in Table 11-1.
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.
Table 11-1. MII Mode
Signal Description
MCF5272 Pin
Transmit clock
E_TxCLK
Transmit enable
E_TxEN
Transmit data
E_TxD[3:0]
Transmit error
E_TxER
Collision
E_COL
Carrier sense
E_CRS
Receive clock
E_RxCLK
Receive enable
E_RxDV
Receive data
E_RxD[3:0]
Receive error
E_RxER
Management channel clock
E_MDC
Management channel serial data
E_MDIO
Table 11-2. Seven-Wire Mode Configuration
Signal Description
MCF5272 Pin
Transmit clock
E_TxCLK
Transmit enable
E_TxEN
Transmit data
E_TxD[0]
Collision
E_COL
Receive clock
E_RxCLK
Summary of Contents for DigitalDNA ColdFire MCF5272
Page 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Page 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Page 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Page 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Page 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Page 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Page 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Page 338: ...13 44 MCF5272 User s Manual Application Examples ...
Page 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Page 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Page 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Page 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...