H1102 datasheet(28/54 Pages) MICREL

28 / 54 page

Micrel, Inc.

KSZ8041NL/RNL

September 2010

M9999-090910-1.4

The KSZ8041RNL RMII pin connections to the MAC are shown in Figure 3.

Figure 3. KSZ8041RNL RMII Interface

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. It is disabled by writing a one to register 1F bit 13. MDI and MDI-X mode is

selected by register 1F 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.

The IEEE 802.3 Standard defines MDI and MDI-X as follows:

MDI

MDI-X

RJ-45 Pin

Signal

RJ-45 Pin

Signal

TD+

RD+

TD-

RD-

RD+

TD+

RD-

TD-

Table 5. MDI/MDI-X Pin Definition

H1102 Datasheet(PDF) 28 Page - Micrel Semiconductor