KSZ8862-16_10 MICREL [Micrel Semiconductor], KSZ8862-16_10 Datasheet - Page 28

• Manufacturer Part Number: KSZ8862-16_10
• Description: 2-Port Ethernet Switch with Non-PCI Interface and Fiber Support
• Manufacturer: MICREL [Micrel Semiconductor]

LinkMD
The KSZ8862M LinkMD
problems such as open circuits, short circuits, and impedance mismatches.
LinkMD
the shape of the reflected signal. Timing the pulse duration gives an indication of the distance to the cabling fault with a
maximum distance of 200m and an accuracy of +/–2m. Internal circuitry displays the TDR information in a user-readable
digital format in register P2VCT [8:0].
Note: cable diagnostics are only valid for copper connection (port 2) –fiber-optic operation is not supported.
Access
LinkMD
P2CR4, the 100BASE-TX PHY Controller register.
Usage
LinkMD
P2CR4 [10] for port 2 to enable manual control over the pair used to transmit the LinkMD
diagnostic test enable bit P2VCT [15] for port 2, is set to ‘1’ to start the test on this pair.
When bit P2VCT [15] returns to ‘0’, the test is complete. The test result is returned in bits P2VCT [14:13] and the distance
is returned in bits P2VCT [8:0]. The cable diagnostic test results are as follows:
If P2VCT [14:13] =11, this indicates an invalid test, and occurs when the KSZ8862M is unable to shut down the link
partner. In this instance, the test is not run, as it is not possible for the KSZ8862M to determine if the detected signal is a
reflection of the signal generated or a signal from another source.
Cable distance can be approximated by the following formula:
P2VCT [8:0] X 0.4m for port 2 cable distance
This constant may be calibrated for different cabling conditions, including cables with a velocity of propagation that varies
significantly from the norm.
Micrel, Inc.
August 2010
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works by sending a pulse of known amplitude and duration down the MDI and MDI-X pairs and then analyzes
can be run at any time by making sure Auto MDIX has been disabled. To disable Auto-MDIX, write a ‘1’ to
Cable Diagnostics
is initiated by accessing register P2VCT, the LinkMD
00 = Valid test, normal condition
01 = Valid test, open circuit in cable
10 = Valid test, short circuit in cable
11 = Invalid test, LinkMD
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uses Time Domain Reflectometry (TDR) to analyze the port 2 cabling plant for common cabling
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failed
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Control/Status register, in conjunction with register
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pulse. The self-clearing cable
KSZ8862-16/32MQL
M9999-081310-3.1