LU82551QM Intel, LU82551QM Datasheet - Page 12

• Manufacturer Part Number: LU82551QM
• Manufacturer: Intel

Specifications of LU82551QM

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 196
• Lead Free Status / RoHS Status: Compliant

82551QM — Networking Silicon
3.3
3.4
6
Hardware Integrity Support
Cabling problems are a common cause for network downtime situations. Hardware Integrity
(HWI) can help reduce this by locating cabling problems, which reduces Total Cost of Ownership
(TCO). It uses transmission line theory to measure the arrival time and electrical characteristics of
the wave reflected from an incident test wave launched on the media. With these measurements,
opens, shorts, and degraded cable quality can be located along the wire.
HWI is controlled and activated by software. The Hardware Integrity Control, register 29 of the
MDI Registers, is used for activating HWI
Control
Management Data Interface MDI/MDI-X Feature
The 82551QM controller MDI/MDI-X feature provides the ability to automatically detect the
required cable connection type and configure the controller-side MAU to the cable type. This
feature effectively allows all properly wired Ethernet cables usable with any Ethernet device to be
connected to the 82551QM without any additional external logic.
This advanced feature enables auto-correction of incorrect cabling with respect to cross-over
versus straight-through cables. The 82551QM can identify the cable connection type and adjust its
MDI port to the cable by switching between the TD and RD pairs. The auto-switching is done prior
to the start of the hardware auto negotiation algorithm.
In a standard straight-through RJ-45 port configuration, the transmit pair is on contacts 1 and 2, and
the receive pair on contacts 3 and 6. These are defined by Clause 23.7.1 of the IEEE 802.3u
standard.
Table 1
Table 1.
lists the connections for both straight-through and cross-over RJ-45 ports for comparison.
Register”).
RJ-45 Connections
a.
b.
1
2
3
4
5
6
7
8
Contact
RJ-45
Straight-through connections used on DTE applications.
Cross-over connections used on Hub and Switch applications.
TD+
TD-
RD+
Not Used
Not Used
RD-
Not Used
Not Used
Straight-Through
MDI Signal
a
(Section 11.3.14, “Register 29: Hardware Integrity
RD+
RD-
TD+
Not Used
Not Used
TD-
Not Used
Not Used
Cross-Over MDIX
Signal
b
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