Motorola MPC8260 - Manual (Page 671)

MOTOROLA Chapter 24. SCC Ethernet Mode 24-3
Part IV. Communications Processor Module
24.2 Features
The following list summarizes the main features of the SCC in Ethernet mode:
¥ Performs MAC layer functions of Ethernet and IEEE 802.3
¥ Performs framing functions
Ñ Preamble generation and stripping
Ñ Destination address checking
Ñ CRC generation and checking
Ñ Automatically pads short frames on transmit
Ñ Framing error (dribbling bits) handling
¥ Full collision support
Ñ Enforces the collision (jamming)
Ñ Truncated binary exponential backoff algorithm for random wait
Ñ Two nonaggressive backoff modes
Ñ Automatic frame retransmission (until the attempt limit is reached)
Ñ Automatic discard of incoming collided frames
Ñ Delay transmission of new frames for speciÞed interframe gap
¥ Maximum 10 Mbps bit rate
¥ Optional full-duplex support
¥ Back-to-back frame reception
¥ Detection of receive frames that are too long
¥ Multibuffer data structure
¥ Supports 48-bit addresses in three modes
Ñ PhysicalÐOne 48-bit address recognized or 64-bin hash table for physical
addresses
Ñ LogicalÐ64-bin group address hash table plus broadcast address checking
Ñ PromiscuousÐReceives all addresses, but discards frame if REJECT is asserted
¥ External content-addressable memory (CAM) support on serial bus interfaces
¥ Up to eight parallel I/O pins can be sampled and appended to any frame
¥ Optional heartbeat indication
¥ Transmitter network management and diagnostics
Ñ Lost carrier sense
Ñ Underrun
Ñ Number of collisions exceeded the maximum allowed