Motorola MPC8260 - Manual (Page 877)

MOTOROLA Chapter 30. Fast Ethernet Controller 30-3
Part IV. Communications Processor Module
Figure 30-2. Ethernet Block Diagram
30.2 Features
The following is a list of Fast Ethernet key features:
¥ Support for Fast Ethernet through the MII (media-independent interface)
¥ Performs MAC (media access control) layer functions of Fast Ethernet and IEEE
802.3x
¥ Performs framing functions
Ñ Preamble generation and stripping
Ñ Destination address checking
Ñ CRC generation and checking
Ñ Automatic padding of short frames on transmit
Ñ Framing error (dribbling bits) handling
¥ Full collision support
Ñ Enforces the collision (jamming and TX_ER assertion)
Ñ Truncated binary exponential backoff algorithm for random wait
Ñ Two nonaggressive backoff modes
Ñ Automatic frame retransmission (until retry limit is reached)
Ñ Automatic discard of incoming collided frames
Ñ Delay transmission of new frames for speciÞed interframe gap
¥ Bit rates up to 100 Mbps
¥ Receives back-to-back frames
¥ Detection of receive frames that are too long
Shifter
Receive Receiver
Control
UNIT FIFO
Shifter
Transmit Transmitter
Control
Unit FIFO
Slot Time
Clock
Generator
Internal Clocks
Control
Registers
TXD[3Ð0] RXD[3Ð0]
Peripheral Bus
60x-Bus
Data Data
RX_CLK
TX_CLK
And Defer
Counter
TX_ER
Random No.
CRS CRS
COL
RX_ER
TX_EN
COL RX_DV