Datasheet

 2016-2018 Microchip Technology Inc. DS00002202C-page 17

KSZ8081MNX/RNB

FIGURE 3-1: AUTO-NEGOTIATION FLOW CHART

3.2 MII Interface (KSZ8081MNX Only)

The Media Independent Interface (MII) is compliant with the IEEE 802.3 Specification. It provides a common interface

between MII PHYs and MACs, and has the following key characteristics:

• Pin count is 15 pins (6 pins for data transmission, 7 pins for data reception, and 2 pins for carrier and collision 

indication).

•10 Mbps and 100 Mbps data rates are supported at both half- and full-duplex.

• Data transmission and reception are independent and belong to separate signal groups.

• Transmit data and receive data are each 4 bits wide, a nibble.

By default, the KSZ8081MNX is configured to MII mode after it is powered up or hardware reset with the following:

A 25 MHz crystal connected to XI, XO (pins 9, 8), or an external 25 MHz clock source (oscillator) connected to XI.

The CONFIG[2:0] strapping pins (pins 18, 29, 28) set to 000 (default setting).

START AUTO-NEGOTIATION

FORCE LINK SETTING

LISTEN FOR 10BASE-T

LINK PULSES

LISTEN FOR 100BASE-TX

IDLES

ATTEMPT AUTO-

NEGOTIATION

LINK MODE SET

BYPASS AUTO-NEGOTIATION

AND SET LINK MODE

LINK MODE SET?

PARALLEL

OPERATION

YES

JOIN FLOW