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TM4C129DNCPDT: MDC/MDIO accessing of PHY using controller

Part Number: TM4C129DNCPDT
Other Parts Discussed in Thread: DP83869HM,


We are trying to access DP83869HM PHY using the TM4C129DNCPDT microcontroller. We have manually programmed but the PHY is not responding(0xFFFF) . Is there any MDC/MDIO example program availabe for TM4C129DNCPDT contoller to access PHY in clause 22?



  • Hi,

      Sorry, we don't have any example demonstrating MDC/MDIO. I will suggest you check a few things.

      - Do you see any activities on the MDIO/MDC pins?

      - Have you configure MDIO/MDC pins? TheMDC/MDIO pins are by default GPIO pins. You need to configure them for MDC/MDIO functionality. 

      - Make sure you disable the internal PHY. For TM4C1292, internal PHY should not be visible. But still disable it to see if it makes a difference. 

      - PHY addresses 1 to 31 is used to select external PHY. 0 is for the integrated PHY. Make sure you don't set 0 in PLA field in the EMACMIIADDR register.