ksz8051mlli Micrel Semiconductor, ksz8051mlli Datasheet - Page 21

• Manufacturer Part Number: ksz8051mlli
• Description: 10base-t/100base-tx Physical Layer Transceiver
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
HP Auto MDI/MDI-X
HP Auto MDI/MDI-X configuration eliminates the confusion of whether to use a straight cable or a crossover cable
between the KSZ8051MLL and its link partner. This feature allows the KSZ8051MLL to use either type of cable to connect
with a link partner that is in either MDI or MDI-X mode. The auto-sense function detects transmit and receive pairs from
the link partner, and then assigns transmit and receive pairs of the KSZ8051MLL accordingly.
HP Auto MDI/MDI-X is enabled by default. It is disabled by writing a one to register 1Fh, bit 13. MDI and MDI-X mode is
selected by register 1Fh, bit 14 if HP Auto MDI/MDI-X is disabled.
An isolation transformer with symmetrical transmit and receive data paths is recommended to support auto MDI/MDI-X.
Table 4 illustrates how the IEEE 802.3 Standard defines MDI and MDI-X.
Straight Cable
A straight cable connects a MDI device to a MDI-X device, or a MDI-X device to a MDI device. Figure 4 depicts a typical
straight cable connection between a NIC card (MDI) and a switch, or hub (MDI-X).
July 2010
RJ-45 Pin
1
2
3
6
Figure 4. Typical Straight Cable Connection
MDI
Table 4. MDI/MDI-X Pin Definition
Signal
RX+
TX+
RX-
TX-
21
RJ-45 Pin
1
2
3
6
MDI-X
Signal
RX+
TX+
RX-
TX-
M9999-071210-1.0
KSZ8051MLL