LPC2458 NXP Semiconductors, LPC2458 Datasheet - Page 27
Manufacturer Part Number
NXP Semiconductors designed the LPC2458 microcontroller around a 16-bit/32-bitARM7TDMI-S CPU core with real-time debug interfaces that include both JTAG andembedded trace
NXP USA Inc.
Product data sheet
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 LPC2458 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.
Ethernet standards support:
– Supports 10 Mbit/s or 100 Mbit/s PHY devices including 10 Base-T, 100 Base-TX,
– 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.
– 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 Circular
– 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.
– Wake-on-LAN power management support allows system wake-up: using the
100 Base-FX, and 100 Base-T4.
Redundancy Check (CRC) for transmit.
receive filters or a magic frame detection filter.
All information provided in this document is subject to legal disclaimers.
Rev. 4 — 1 September 2011
Single-chip 16-bit/32-bit micro
© NXP B.V. 2011. All rights reserved.
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