Fast Ethernet Controller (FEC)
16-4
Freescale Semiconductor
MCF51CN128 Reference Manual, Rev. 6
16.2.1
Full and Half Duplex Operation
Full duplex mode is for use on point-to-point links between switches or end node to switch. Half duplex
mode works in connections between an end node and a repeater or between repeaters. TCR[FDEN]
controls duplex mode selection.
When configured for full duplex mode, flow control may be enabled. Refer to the
TCR[RFC_PAUSE,TFC_PAUSE] bits, the RCR[FCE] bit, and
Section 16.5.11, “Full Duplex Flow
16.2.2
Interface Options
The following interface options are supported. A detailed discussion of the interface configurations is
provided in
Section 16.5.6, “Network Interface Options.”
16.2.2.1
10 Mbps and 100 Mbps MII Interface
The IEEE 802.3 standard defines the media independent interface (MII) for 10/100 Mbps operation. The
MAC-PHY interface may be configured to operate in MII mode by setting RCR[MII_MODE].
FEC_TXCLK and FEC_RXCLK pins driven by the external transceiver determine the operation speed.
The transceiver auto-negotiates the speed or software controls it via the serial management interface
(FEC_MDC/FEC_MDIO 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.
16.2.2.2
10 Mpbs 7-Wire Interface Operation
The FEC supports 7-wire interface used by many 10 Mbps Ethernet transceivers. The RCR[MII_MODE]
bit controls this functionality. If this bit is cleared, MII mode is disabled and the 10 Mbps 7-wire mode is
enabled.
16.2.3
Address Recognition Options
The address options supported are promiscuous, broadcast reject, individual address (hash or exact match),
and multicast hash match. Address recognition options are discussed in detail in
16.2.4
Internal Loopback
Internal loopback mode is selected via RCR[LOOP]. Loopback mode is discussed in detail in
Section 16.5.14, “MII Internal and External Loopback.”
16.3
External Signal Description
describes the various FEC signals, as well as indicating which signals work in available modes.
