Datasheet

LPC2468 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6.2 — 11 January 2013 31 of 85
NXP Semiconductors
LPC2468
Single-chip 16-bit/32-bit micro
7.10 Ethernet
The Ethernet block contains a full featured 10 Mbit/s or 100 Mbit/s Ethernet MAC
designed to provide optimized performance through the use of DMA hardware
acceleration. Features include a generous suite of control registers, half or full duplex
operation, flow control, control frames, hardware acceleration for transmit retry, receive
packet filtering and wake-up on LAN activity. Automatic frame transmission and reception
with scatter-gather DMA off-loads many operations from the CPU.
The Ethernet block and the CPU share a dedicated AHB subsystem that is used to access
the Ethernet SRAM for Ethernet data, control, and status information. All other AHB traffic
in the LPC2468 takes place on a different AHB subsystem, effectively separating Ethernet
activity from the rest of the system. The Ethernet DMA can also access off-chip memory
via the EMC, as well as the SRAM located on another AHB. However, using memory
other than the Ethernet SRAM, especially off-chip memory, will slow Ethernet access to
memory and increase the loading of its AHB.
The Ethernet block interfaces between an off-chip Ethernet PHY using the Media
Independent Interface (MII) or Reduced MII (RMII) protocol and the on-chip Media
Independent Interface Management (MIIM) serial bus.
7.10.1 Features
• Ethernet standards support:
– Supports 10 Mbit/s or 100 Mbit/s PHY devices including 10 Base-T, 100 Base-TX,
100 Base-FX, and 100 Base-T4.
– Fully compliant with IEEE standard 802.3.
– Fully compliant with 802.3x Full Duplex Flow Control and Half Duplex back
pressure.
– Flexible transmit and receive frame options.
– Virtual Local Area Network (VLAN) frame support.
• Memory management:
– Independent transmit and receive buffers memory mapped to shared SRAM.
– DMA managers with scatter/gather DMA and arrays of frame descriptors.
– Memory traffic optimized by buffering and pre-fetching.
• Enhanced Ethernet features:
– Receive filtering.
– Multicast and broadcast frame support for both transmit and receive.
– Optional automatic Frame Check Sequence (FCS) insertion with Cyclic
Redundancy Check (CRC) for transmit.
– Selectable automatic transmit frame padding.
– Over-length frame support for both transmit and receive allows any length frames.
– Promiscuous receive mode.
– Automatic collision back-off and frame retransmission.
– Includes power management by clock switching.