Modes of Operation

Automatic internal flushing of the receive FIFO for runts (collision fragments) and address recognition rejects (no processor bus utilization)

Address recognition

Frames with broadcast address may be always accepted or always rejected

Exact match for single 48-bit individual (unicast) address

Hash (64-bit hash) check of individual (unicast) addresses

Hash (64-bit hash) check of group (multicast) addresses

Promiscuous mode

17.2 Modes of Operation

The primary operational modes are described in this section.

17.2.1 Full and Half Duplex Operation

Full duplex mode is intended for use on point to point links between switches or end node to switch. Half duplex mode is used in connections between an end node and a repeater or between repeaters. Selection of the duplex mode is controlled by TCR[FDEN].

When configured for full duplex mode, flow control may be enabled. Refer to the TCR[RFC_PAUSE] and TCR[TFC_PAUSE] bits, the RCR[FCE] bit, and Section 17.4.10, “Full Duplex Flow Control,” for more details.

17.2.2 Interface Options

The following interface options are supported. A detailed discussion of the interface configurations is provided in Section 17.4.5, “Network Interface Options”.

17.2.2.1 10 Mbps and 100 Mbps MII Interface

MII is the Media Independent Interface defined by the IEEE 802.3 standard for 10/100 Mbps operation. The MAC-PHY interface may be configured to operate in MII mode by asserting RCR[MII_MODE].

The speed of operation is determined by the ETXCLK and ERXCLK pins which are driven by the external transceiver. The transceiver will either auto-negotiate the speed or it may be controlled by software via the serial management interface (EMDC/EMDIO pins) to the transceiver. Refer to the MMFR and MSCR register descriptions as well as the section on the MII for a description of how to read and write registers in the transceiver via this interface.

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MCF5282 User’s Manual

MOTOROLA

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Motorola MCF5282, MCF5281 Full and Half Duplex Operation, Interface Options, 17.2.2.1 10 Mbps and 100 Mbps MII Interface