UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 216 o f 792
NXP Semiconductors UM10237
Chapter 11: LPC24XX Ethernet

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.

6. Pin description

Table11–183 shows the signals used for connecting the Media Independent Interface

(MII), and Table11–184 shows the signals used for connecting the Reduced Media

Independent Interface (RMII) to the external PHY.

Fig 27. Ethernet packet fields

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

Table 183. Ether net MII pin descriptions

Pin Name Type Pin Description

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.