• State
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 68 views
  • Users 0 members are here
Support feedback
Options
Options
Related

TPS25821: USB C-Communication not possible

Gyuner Idrizov
Prodigy 30 points
Part Number: TPS25821

Tool/software:

Hello, 

we are using TPS25821 as source device to charge the external devices but we want to have also possibility to update the firmware of our electronics (over computer USB-C connection).

When we use USB-A to USB-C cabel we have the communication and firmware update is possible but not with USB-C to USB-C cabel.

Our electronic will be supplied in both cases externally.

What could be the problem that we do not have communication with computer USB-C ports?

  • 0
    TI__Mastermind 32641 points

    Hi Gyuner,

    A USB-A to USB-C cable will have an internal 5.1K ohm resistor pull down on the CC 1line connected to the type-C connector.  It will not impact the USB lines.

    What protocol structure do you plan to use for your update?  I can't really help describe what could be wrong without knowing the details of the signaling and how the CC lines are utilized in the system.

    Regards,

    Chuck

  • 0 in reply to Chuck Branch
    Prodigy 30 points

    CC lines will be controlled by TPS25821

  • 0 in reply to Chuck Branch
    Prodigy 30 points

    protobuf is used for communication. 

  • 0 in reply to Gyuner Idrizov
    TI__Mastermind 32641 points

    Hi Gyuner,

    If you are using the D+/D- lines for your physical layer connection, then the TPS25821 does not have any impact on the data link.

    The TPS25831 will detect if the CC lines offer a source or sink connection and will close the IN to OUT switch appropriately.

    In the case of an A to C cable, there will be a 5.1K RD on either CC1 or CC2 of the cable and the TPS25821 will drive VBUS in this condition.

    Are you able to provide a scope plot of VBUS, CC1, and CC2 during your failure?  This may allow me to see what is happening systematically.

    Regards,

    Chuck