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matas
matas
Associate III
September 25, 2015
Question

STM32 with integrated phy

  • September 25, 2015
  • 4 replies
  • 1610 views
Posted on September 25, 2015 at 12:28

Hey, is there an STM32 device which would have an integrated phy and would only require an RJ45 jack for LAN interface? I tried to look for it, but I could not find it.

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    4 replies

    waclawek.jan
    waclawek.jan
    Super User
    September 25, 2015
    Posted on September 25, 2015 at 12:41

    No.

    JW
    jpeacock
    jpeacock
    Associate
    September 25, 2015
    Posted on September 25, 2015 at 13:56

    The problem with an integrated PHY is the power required to drive the transformer coil in the connector magnetics.  The old Stellaris parts (now TI) tried this but if you look at the parts there were so many power and ground pins not much was left over for GPIO or other functions.  It looked like a great idea but didn't work so well in practice.

    The other reason for an external PHY is the requirement for multiple buses.  With the right PHY the MAC port can share two or more separate Ethernet buses, important if you want redundant paths for reliable communications.

      Jack Peacock
    matas
    matasAuthor
    Associate III
    September 28, 2015
    Posted on September 28, 2015 at 09:09

    Thanks for the explanation :)

    Foo Bar
    Joerg Wagner
    Joerg Wagner
    Senior III
    December 30, 2017
    Posted on December 31, 2017 at 00:06

    Well, there are a bunch of microcontroller on the market with an integrated PHY. These devices have a MDI interface and just 4 lines are needed. A popular one is the W7500P.

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