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Re: MDIO interface address/ID


The mechanism for defining the port and device address is not specified by the
standard and is implementation specific. However, existing Clause 22 devices
have set a sensible precident for Clause 45 devices that it would be wise to
The device type that a particular device will respond to should be hard coded
when the device is designed. For example, when the MDIO logic block of a WIS is
being designed then it should be coded so that it only responds to accesses to
WIS devices.
The port address should be configurable at the time the board is designed and
Clause 22 devices usually provide five pins which can be pulled high and low by
resistors on the PCB.  The port address should not need to change during
Each device has to check each and every MDIO frame to make sure that the device
type matches its own hard coded device type and the port type matches is own
port type that has been set through the external pins.

Clause 45 editor.

Steven Shen <ss_shen@xxxxxxxxxxxxxxxxx> on 25/01/2001 19:00:09

Sent by:  Steven Shen <ss_shen@xxxxxxxxxxxxxxxxx>

To:   "stds-802-3-hssg" <stds-802-3-hssg@xxxxxxxx>
cc:    (Edward Turner/GB/3Com)
Subject:  MDIO interface address/ID


MDIO interface, each MDIO supports 32 ports, and each port supports 32
Is there any universal mechanism to define how to set the default port
address and device address for
each attached device.
When each device receive a MDIO frame, does it check the port address
and device address against its own?

Best Regards
Steven Shen
Silicon Bridge Inc.