Data Sheet

Ethernet Controller I210 —Design Considerations

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12.5.5 Designing the I210 as a 10/100 Mb/s Only Device

To connect the I210 as a 10/100 Mb/s only device:

1. Set bit 4 of the Software Defined Pins Control (LAN Base Address + Word 0x20) to 0b. Setting bit 4

to 1b disables 1000 Mb/s (GbE) operation in all power modes (see Section 6.2.21).

2. Connect MDI pair 0 (pins 57 and 58) and MDI pair 1 (pins 54 and 55) to your magnetics. MDI pair

2 (pins 52 and 53) and MDI pair 3 (pins 49 and 50) can each be pulled up to 1.9 V dc through a

50  resistor or connected to the magnetics as a GbE device if it is desired at a later time to enable

GbE by altering bit 4 of the Software Defined Pins Control (LAN Base Address + Word 0x20; Giga

Disable). See Figure 12-11 and Figure 12-12 for details.

3. Use one of the approved discrete GbE magnetics that were tested with the I210 (refer to

Section 12.5.3). Note that Intel has not tested any 10/100 magnetics with the I210.

Note: If you must use 10/100 magnetics in your design with the I210, the magnetics must

have a Common Mode Choke (CMC) in the receive path.

The I210 supports auto-MDIX; this feature CANNOT be disabled. If there is no CMC in the receive path,

the system most likely will not pass regulatory radiated emission tests when MDI-X mode is used.

Figure 12-11.I210 Gigabit Magnetics Module Connections

I210

MD I_PLU S (0)

MDI_MINUS (0)

MD I_PLU S (1)

MDI_MINUS (1)

MD I_PLU S (2)

MDI_MINUS (2)

MD I_PLU S (3)

MDI_MINUS (3)

Gigabit Magnetics

Module