AN2692 Freescale Semiconductor / Motorola, AN2692 Datasheet - Page 18

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

MC9S12NE64 Ethernet Media Access Controller (EMAC)
Hardware MAC Address
Each network device should have a unique 6-byte media access control (MAC) hardware address that
identifies that device on a network. A valid MAC hardware address should be assigned by the developer.
This address is used by the datalink layer, which is implemented by the MC9S12NE64 integrated Ethernet
controller and low-level drivers. If the device is not connected to a real network, a random MAC hardware
address can be used as long as no other device with the same 6-byte MAC hardware address is on the
same network.
MAC hardware address groups are assigned by the IEEE EtherType Field Registration Authority. The
IEEE-assigned MAC hardware address group is defined by the upper 24-bits of the MAC address. This
MAC hardware address group is called the organizational unique identifier (OUI). The lower 24-bits of the
MAC address are specified by the vendor as a serial number in most cases. The user must obtain a MAC
hardware address group for products that use the MC9S12NE64.
The assigned MAC hardware address must be programmed into the MAC unicast address (MACAD)
register in FLASH memory. These registers are one-time writable after reset.
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Table 1. MII Signal Descriptions (Continued)
MC9S12NE64 Integrated Ethernet Controller, Rev. 0.2
Pin MII Function
EXTPHY Bit Set
(EXTPHY = 1)
MII_TXCLK
MII_RXD3
MII_RXD2
MII_RXD1
MII_RXD0
MII_TXER
MII_TXEN
MII_MDIO
MII_TXD3
MII_TXD2
MII_TXD1
MII_TXD0
MII_MDC
MII_CRS
MII_COL
Receive data 3
Receive data 2
Receive data 1
Receive data 0
Transmit error
Transmit data enable
Transmit clock
Transmit data 3
Transmit data 2
Transmit data 1
Transmit data 0
Collision detected
Carrier sense
Management data I/O
Management data clock
MII Signal Description
Freescale Semiconductor