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Does AM335x support "Serial Management Interface"?

g.f.
Guru 15520 points
Other Parts Discussed in Thread: AM3352, TLK100

Hi,

I have a question about AM3352.

Does AM3352 MDIO supports SMI(Serial Management Interface)?
I want to connect Ether Switch Hub to AM3352 via SMI.

best regards,
g.f.

  • 0
    TI__Guru**** 393215 points
    Hi g.f,
     
    AM335X TRM, Rev.H, Section 14.3.8 MDIO:

    The MII Management I/F module implements the 802.3 serial management interface to interrogate and control two Ethernet PHYs simultaneously using a shared two-wire bus. Two user access registers to control and monitor up to two PHYs simultaneously.

  • 0 in reply to Biser Gatchev-XID
    Guru 15520 points

    Hi Biser,

    Thank you so much.
    I understood that AM335x MDIO supports the SMI.
    And I'm sorry that the check of TRM was insufficient.

    best regards,
    g.f.

  • 0 in reply to Biser Gatchev-XID
    Guru 15520 points

    Hi Biser,

    I have another question about AM335x Ether.

    In TRM page.1231, MDIO Frame Format "Operation Code" is written as follow:
    =================================================
    The operation code for a read is “10”,
    while the operation code for a write is a “00”.
    ==================================================

    I guess operation code for write is "01" because
    when I checked some PHY data sheet(for example TI TLK100),
    operation code was "01".
    In other data sheet, it also written "01" for write operation code.

    Is this miss print of AM335x TRM?

    One more question.
    Our Micrel PHY supports SMI Frame Fortmat but
    I don't know how to use this format in AM335x.
    To do SMI register access in Micrel PHY,
    we need to send "00" operation code for read access also write access.
    Is there anyway to send "00" for operation code from AM335x to Ether PHY?

    best regards,
    g.f.

  • 0 in reply to g.f.
    TI__Guru**** 393215 points
    I guess this is a typo in the TRM. Opcode for write is indeed "01". Bug has been submitted to TRM team.
     
    I think the opcodes are hard-coded in the AM335X. At least there is no MDIO register where you can enter them freely. There is only a register bit for read/write.
  • 0 in reply to Biser Gatchev-XID
    Guru 15520 points

    Hi Biser,

    Thank you so much.

    Please let me ask again to make sure.

    Opcode is sent based on a MDIOUSERACCESSn register setup, right?
    Which means if I setup MDIOUSERACCESSn.WRITE='1',
    "01"opcode is sent automatically for write access.

    So, it is able to send "10" and "01" opcode
    but there are no way to send "00"opcode, right?

    best regard,
    g.f.

  • 0 in reply to g.f.
    TI__Guru**** 393215 points
    Yes, I think this is how it works.
  • 0 in reply to Biser Gatchev-XID
    Guru 15520 points

    Hi Biser,

    Thank you so much.
    I understood.

    best regards,
    g.f.