KSZ8041NL/RNL
3.16 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 KSZ8041NL/RNL and its link partner. This feature allows the KSZ8041NL/RNL 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 KSZ8041NL/RNL accordingly.
HP Auto MDI/MDI-X is enabled by default. Writing “1” to register 1F bit 13 disables HP Auto MDI/MDL-X. Register 1F
bit 14 selects MDI and MDI-X mode 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.
The IEEE 802.3 Standard MDI and MDI-X is defined in Table 3-5.
TABLE 3-5:
MDI/MDI-X PIN DESCRIPTION
MDI
MDI-X
RJ-45 Pin
Signal
RJ-45 Pin
Signal
1
2
3
6
TD+
TD–
RD+
RD–
1
2
3
6
RD+
RD–
TD+
TD–
2017 Microchip Technology Inc.
DS00002245B-page 25
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