KSZ8041TL-S Micrel Inc, KSZ8041TL-S Datasheet - Page 34

• Manufacturer Part Number: KSZ8041TL-S
• Description: IC TXRX PHY 10/100 BASE 48TQFP
• Manufacturer: Micrel Inc
• Type: Transceiverr

Specifications of KSZ8041TL-S

• Number Of Drivers/receivers: 1/1
• Protocol: SMII
• Voltage - Supply: 3.135 V ~ 3.465 V
• Mounting Type: Surface Mount
• Package / Case: 48-TQFP, 48-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3626; KSZ8041TL-S

Micrel, Inc.
LinkMD
The LinkMD
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
maximum distance of 200m and accuracy of +/-2m. Internal circuitry computes the TDR information and presents it in a
user-readable digital format.
Note: Cable diagnostics are only valid for copper connections and do not support fiber optic operation.
Access
LinkMD
PHY Control 2 Register.
Usage
The following test procedure demonstrates how to use LinkMD
Power Management
The KSZ8041TL/FTL/MLL offers the following power management modes:
Power Saving Mode
This mode is used to reduce power consumption when the cable is unplugged. It is in effect when auto-negotiation mode
is enabled, cable is disconnected, and register 1Fh bit 10 is set to 1. Under power saving mode, the KSZ8041TL/FTL/MLL
shuts down all transceiver blocks, except for transmitter, energy detect and PLL circuits. Additionally, in MII mode, the
RXC clock output is disabled. RXC clock is enabled after the cable is connected and link is established.
Power saving mode is disabled by writing a zero to register 1Fh bit 10.
Power Down Mode
This mode is used to power down the entire KSZ8041TL/FTL/MLL device when it is not in use. Power down mode is
enabled by writing a one to register 0h bit 11. In the power down state, the KSZ8041TL/FTL/MLL disables all internal
functions, except for the MII management interface.
December 2009
1. Disable auto MDI/MDI-X by writing a ‘1’ to register 1Fh bit 13 to enable manual control over the differential pair
2. Select the differential pair to transmit the LinkMD
3. Start cable diagnostic test by writing a ‘1’ to register 1Dh bit 15. This enable bit is self-clearing.
4. Wait (poll) for register 1Dh bit 15 to return a ‘0’, indicating cable diagnostic test is completed.
5. Read cable diagnostic test results in register 1Dh bits [14:13]. The results are as follows:
6. Get distance to fault by multiplying the decimal value in register 1Dh bits [8:0] by a constant of 0.4. The distance,
The 0.4 constant can be calibrated for different cable types and cabling conditions, such as cables with velocity of
propagation that varies significantly from the norm.
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used to transmit the LinkMD
The ‘11’ case, invalid test, occurs if the KSZ8041TL/FTL/MLL is unable to shut down the link partner. In this
instance, the test is not run, since it would be impossible for the KSZ8041TL/FTL/MLL to determine if the detected
signal is a reflection of the signal generated by the KSZ8041TL/FTL/MLL, or a signal from its link partner.
D (expressed in meters), to the cable fault is determined by the following formula:
works by sending a pulse of known amplitude and duration down the MDI and MDI-X pairs, and then analyzing
is initiated by accessing register 1Dh, the LinkMD
Cable Diagnostics
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feature utilizes time domain reflectometry (TDR) to analyze the cabling plant for common cabling problems,
00 = normal condition (valid test)
01 = open condition detected in cable (valid test)
10 = short condition detected in cable (valid test)
11 = cable diagnostic test failed (invalid test)
D (distance to cable fault) = 0.4 x {decimal value of register 1Dh bits [8:0]}
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pulse.
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pulse with register 1Fh bit 14.
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Control/Status Register, in conjunction with register 1Fh, the
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for cable diagnostic:
KSZ8041TL/FTL/MLL
M9999-120909-1.2