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TM4C1294NCPDT: TM4C1294NCPDT how to connect MDC/MDIO LINES

Part Number: TM4C1294NCPDT
Other Parts Discussed in Thread: TM4C1292NCPDT

With TM4C1294NCPDT i want to manage / control the external phy using MDC, MDIO lines.

For this purpose can I use any i2c lines? or any dedicated pins are available for MDC/MDIO Interface? 

The requirement is only to control the MDC, MDIO lines (to read/ write the registers of external phy).

  • Hello Guru,

    To the direct question of using I2C for MDC / MDIO control, from what I can see that is not possible. You'd need a dedicated interface for that to handle timing and packet requirements.

    However I am not understanding this request as a whole... TM4C1294NCPDT has an integrated Ethernet MAC + PHY. You don't need an external PHY if you use this MCU. So I think your issue is solved simply that you just need to create the hardware connections to the Ethernet jack and do not need an additional PHY chip on your PCB.

  • Hello Ralph Jacobi,

    Yes, there is intergrated ETH in TM4C1294NCPDT.  We are using an ethernet for that.

    In addition to this, we want to control the external MAC via MDC, MDIO lines.

    For this whether TM4C1294NCPDT have any provision? If not, how to handle the external MDC,MDIO lines with TM4C129NCPDT?

  • Hello Guru,

    For the TM4C1294NCPDT there are no provisions to support external MDC and MDIO. This is because the integrated Ethernet MAC + PHY is how to connect over Ethernet with that device.

    For certain other TM4C devices such as the TM4C1292NCPDT, only the Ethernet MAC is integrated and in those cases the Ethernet PHY can be connected to MII or RMII interface which will support MDC / MDIO via the EN0MDC and EN0MDIO signals.