Nxp Semiconductors UM10237 ユーザーズマニュアル

UM10237_2

© NXP B.V. 2008. All rights reserved.

 

A packet consists of a preamble, a start-of-frame delimiter and an Ethernet frame.

The Ethernet frame consists of the destination address, the source address, an optional 
VLAN field, the length/type field, the payload and the frame check sequence.

Each address consists of 6 bytes where each byte consists of 8 bits. Bits are transferred 
starting with the least significant bit.

 shows the signals used for connecting the Media Independent Interface 

(MII), and 

 shows the signals used for connecting the Reduced Media 

Independent Interface (RMII) to the external PHY.

 

OPTIONAL

VLAN

SOURCE

ADDRESS

DesA

oct6

DesA

oct1

DesA

oct2

DesA

oct3

DesA

oct4

DesA

oct5

SrcA

oct6

SrcA

oct5

SrcA

oct4

SrcA

oct3

SrcA

oct2

SrcA

oct1

LSB

oct(0)

oct(1)

oct(2)

oct(3)

oct(4)

oct(5)

oct(6)

MSB

oct(7)

DESTINATION

ADDRESS

PAYLOAD

FCS

ETHERNET FRAME

PREAMBLE
  7 bytes

ethernet packet

start-of-frame

delimiter

1 byte

time

LEN

TYPE

ENET_TX_EN

Output

Transmit data enable.

ENET_TXD[3:0]

Output

Transmit data, 4 bits.

ENET_TX_ER

Output

Transmit error.

ENET_TX_CLK

Input

Transmit clock.