MCF52235 or freescale microcontroller that's support MDIO communication

[jrf_oliveira]

Hello people from Freescale,

I was developing many systems with freescale microcontrollers and microprocessors (MCF52223, MCF5329).

But i am facing a new challenge here and i have a big doubt, there is any way of use the MDIO communication separately from the fast Ethernet controller ?

Because the new optical communications modules has this type of communication protocol. i see that this protocol is like the I2C protocol, but haves some differences. But i see in the FEC controller that exist the MDIO pin and clock pin, but this is used in conjunction with the FEC, because of this i am asking you with there is some way of use this MDIO communication bus in a separated way from FEC ?

Regards,

Juliano Oliveira

[scifi]

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jrf_oliveira wrote:

But i am facing a new challenge here and i have a big doubt, there is any way of use the MDIO communication separately from the fast Ethernet controller ?

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Sure there is a way. As far as I can see, you don't have to use the MDIO part of the FEC. You can safely implement the protocol with bit banging if you like. The FEC's MDIO interface is provided for convenience and/or completeness.

[jrf_oliveira]

Many thanks for your answer scifi. it was very helpfull indeed.

Regards,

Juliano

[mjbcswitzerland]

Hi Juliano

The MDIO is a part of the Ethernet controller and the Ethernet controller needs to be powered to be able to use the MDIO. However the MDIO interface itself doesn't need to be used by the Ethernet interface - it can be used for controlling other interfaces assuming that its bidirectional protocol satisfies the requirements.

The MDIO interface is also not absolutely necessary for working with the Ethernet interface. In some designed it is possible to configure external PHYs purely by HW straps and then never communicate with them.

Furthermore, the MDIO interface can be used to control multiple devices since it is address based. This means that it could be shared with an external Ethernet PHY and another device which needs to be controlled via the same interface - the devices set their data lines to high impendence when they are not addressed and driving data.

Regards

Mark

[jrf_oliveira]

Many thanks Mark, your answer was very helpful, i am helping a friend i my work with this and we will study a litte bit more about the MDIO interface now.