ICS1889 datasheet(3/35 Pages) ICST

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ICS1889

Media Independent Interface (MII)

The ICS1889 implements a fully compliant IEEE 802.3µ

Media Independent Interface for connection to MACs or

repeaters which allows connections between the ICS1889

and MAC on the same board, motherboard/daughter board or

via a cable in a similar manner to AUI connections.

The MII is a specification of signals and protocols which

formalizes the interfacing of a 10/100 Mbps Ethernet Media

Access Controller (MAC) to the underlying physical layer.

The specification is such that different physical media may be

supported (such as 100Base-TX, 100Base-T4 and 100Base-

FX) transparently to the MAC.

The MII specifies transmit and receive data paths. Each path

is 4-bits wide allowing for transmission of a nibble or single

symbol. The transmit data path includes a transmit clock for

synchronous transfer, a transmit enable signal and a transmit

error signal. The receive data path includes a receive data

clock for synchronous transfer, a receive data valid signal and

a receive error signal. Both the transmit clock and receive

clock are sourced by the ICS1889. The ICS1889 provides the

MII signals carrier sense and collision detect. In half duplex

mode, carrier sense indicates that data is being transmitted or

received, and in full duplex mode it indicates that data is

being received. Collision detect indicates that data has been

received while a transmission is in progress.

The MII also specifies a two wire interface and a protocol

between station management and the physical layer. The

ICS1889 implements this interface providing a bidirectional

data line and a clock input for synchronizing the data

transfers. This interface allows station management to read

and write all of the ICS1889 registers.

The ICS1889 is designed to allow hot insertion of an MII

cable into the MAC. During the power-up phase, the

ICS1889 will isolate the MII and the transmit pair by

tristating the PHY outputs.

ICS1889 데이터시트(PDF) 3 Page - Integrated Circuit Systems