AN2692 Freescale Semiconductor / Motorola, AN2692 Datasheet - Page 15

• Manufacturer Part Number: AN2692
• Description: MC9S12NE64 Integrated Ethernet Controller
• Manufacturer: Freescale Semiconductor / Motorola

MC9S12NE64 Ethernet Media Access Controller (EMAC)
The EMAC is an implementation of a media access controller (MAC) as defined by the IEEE 802.3
Ethernet standard. The EMAC implements the data link layer as described in the communication model
shown in
implements the IEEE 802.3 medium-independent interface (MII) standard including the MII management
interface that can be used to set different PHY options and check PHY status. The EMAC also includes
the following features:
The MC9S12NE64 EMAC provides the mechanism for transferring data from the network layer of one
Ethernet-enabled device to another. In the course of these data transfers, the EMAC must also provide
data encapsulation, MAC address handling, and error detection. Data encapsulation is the framing,
delimiting, and conversion of data from the nibble bit (coming to and from the PHY) to data frames or
packets stored in the buffers. In addition, in half-duplex mode, the EMAC provides media access using
carrier sense multiple access/collision detect (CSMA/CD) protocol (see the
Figure 9
EMAC clock source.
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Address recognition and filtering
Promiscuous mode
Ethertype filter
External PHY mode
Flow control with receive detection
Two receive buffers with valid frame received detection
One transmit buffer interface with transmit frame complete detection
Buffer overrun detection
Maximum frame size babbling detection
Frame alignment, CRC, and frame length error detection
MII serial management transfer detection
Late collision and excessive collision detection
Loopback mode
is a block diagram of the EMAC module in the MC9S12NE64 with the internal bus clock as the
Figure
3. The EMAC supports operation at both 10 Mbps and 100 Mbps. The EMAC also
MC9S12NE64 Integrated Ethernet Controller, Rev. 0.2
MC9S12NE64 Ethernet Media Access Controller (EMAC)
Full Duplex (FDX)
section).
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