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DS160PT801: SMBus Interface

John Madsen
Prodigy 30 points
Part Number: DS160PT801

Does the DS160PT801's SMBus interface follow the command formats specified in Intel's "PCIe 4.0 Retimer Supplemental Features" document?

Thanks, John

  • 0
    TI__Mastermind 27925 points

    Hi John,

    The DS160PT801 has two SMBus modes, 8-bit and 16-bit.  When it is in 16-bit mode, it will follow the command formats in the Intel supplemental features document.  The retimer is in 16-bit mode on power up by default.  You can refer on how to switch between the two modes by using the Programming Guide.

    It is important to know that our EVM software, SigCon Architect and Python API, will change the retimer into 8-bit mode when it connects.  Most of the Programming Guide is assuming the retimer is in 8-bit mode.

    Regards,

    Nicholaus

  • 0 in reply to Nicholaus_Malone
    Prodigy 30 points

    Thanks Nicholaus, but I don't think the device strictly follows Intel's command format. I've eventually been able to access the device in 16-bit mode using standard SMBus register reads and writes. I didn't follow the Intel format where each access starts with a command code byte specifying whether PEC checking is enabled, the function, read or write, and start or end-of-transaction indicators. Can you confirm this?

    Thanks, John

  • +1 in reply to John Madsen
    TI__Mastermind 27925 points

    Hi John,

    I see.  Let me look into this and get back to you within 24-hours.

    Regards,

    Nicholaus

  • 0 in reply to Nicholaus_Malone
    TI__Mastermind 27925 points

    Hi John,

    Here is the response.from the design team:

    "The short answer is no. We don’t support the command code format in that Intel document.

    However, we do support the 16-bit offset address register access described in that document. If the device is in 16-bit mode (the power-up setting) and you access the address according to the Intel document, the corresponding registers inside our device will be updated (on write) or returned (on read)"

    So you are correct;  It is similar, but not exactly the same.  Sorry for the confusion.

    Regards,

    Nicholaus