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Original question:

Will TPS6598x support USB Type-C Authentication Specification?

TPS65988: Is authentication for USB-C PD supported with the integrated device features in a DFP application?

Vijay Ravindran
Intellectual 1420 points
Part Number: TPS65988

Hi Team,

A customer is looking into the TPS65988 and is wondering if there is an integrated feature within the TPS65988 that will allow for the device to be used in a USB-C PD application leveraging authentication. What I mean by this - is there a way to verify that the TPS65988 only delivers power/allows data to be transferred to specific devices even if a device properly attaches to the USB-C port? I did not see anything in the datasheet, so I wanted to make sure I didn't miss anything. If there is not an integrated feature I'm also curious if its possible to implement using logic.

Thanks in advance,

Vijay

  • 0
    TI__Mastermind 32711 points

    Vijay,

    The TPS65988 does not directly implement this type of functionality, but it does allow the end user to execute something similar using Vendor Defined Alternate Modes.

    This would allow the end user to create an authentication loop outside of the 998 using an External MCU.

    Regards,

    Chuck

  • 0 in reply to Chuck Branch
    TI__Intellectual 1420 points

    Thanks Chuck I'll relay the information to the customer.

  • 0 in reply to Chuck Branch
    TI__Intellectual 1420 points

    Hi Chuck, sorry to reopen this chain back up. I just want to clarify that in the case of using Vendor Defined Alternate Modes with an external MCU, the process will look like the following:

    1.) Host sends "Discover Identity" command

    2.) UFP receives message and sends "Discover Identity" ACK w/ its identity number

    3.) Host sends "Discover SVID's" command

    4.) UFP receives message, sends ACK w/ SVID list

    5.) Host sends "Discover Modes" command

    6.) UFP receives message, sends ACK w/ different modes

    7.) External MCU flags a certain register if expected Vendor Defined Alternate Mode is not available (prevents "Enter Mode" command from being sent and Host resends "Discover Modes" command)

    8.) If expected Vendor Defined Alternate Mode is available, external MCU removes flag from register and "Enter Mode" command is sent

  • +1 in reply to Vijay Ravindran
    TI__Mastermind 32711 points

    Vijay,

    That is essentially correct.  The thing that I would add in is that the customer can then use Vendor Defined Messages within the Alternate mode to send authentication keys or other information across the bus.

    This allows an external security MCU to be used for authentication.

    Regards,

    Chuck