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3.5 Ethernet Controller
On the board there are two Intel 82551IT Fast Ethernet Controllers mounted.
The 82551IT is an evolutionary addition to Intel's family of 8255x controllers. It provides excellent
performance by offloading TCP, UDP and IP checksums and supports TCP segmentation off-load for
operations such as Large Send. The 82551IT provides an extended operating temperature in addition
to all of the same capabilities and features as the 82551ER to address applications requiring a wider
operating temperature range.
Its optimized 32-bit interface and efficient scatter-gather bus mastering capabilities enable the
82551IT to perform high speed data transfers over the PCI bus. This capability accelerates the
processing of high level commands and operations, which lowers CPU utilization. Its architecture
enables data to flow efficiently from the bus interface unit to the 3 KB Transmit and Receive FIFO's,
providing the perfect balance between the wire and system bus. In addition, multiple priority queues
are provided to prevent data underruns and overruns.
The 82551IT includes both a MAC and PHY. In also has a simple interface to the analog front end,
which allows cost effective designs requiring minimal board real estate. The 82551IT is pin
compatible with the 82559 family of controllers and is offered with software that provides backwards
compatibility with previous 8255xER controllers.
Ethernet Interface
The Ethernet 1 connector is shared with USB 1 and I²C bus.
Connector type IDC10 pin header 2.54 mm
The Ethernet 2 connector uses a single connector
Connector type IDC10 pin header 2.54 mm
TME-104-CLR-LX800-R1V3.doc
Pin
Signal
1
ETH1-TX+
3
ETH1-RX+
5
PE
7
USB0+
9
VCC_USB0
Pin
Signal
1
ETH2-TX+
3
ETH2-RX+
5
PE
7
PE
9
n.c.
Rev. 1.3
Pin
Signal
2
ETH1-TX-
4
PE
6
ETH1-RX-
8
USB0-
10
USB-GND
Pin
Signal
2
ETH2-TX-
4
PE
6
ETH2-RX-
8
PE
10
n.c.
19(53)
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