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TPS65988 Cable orientation with TUSB542

Trang Pham
Prodigy 35 points
Part Number: TUSB542
Other Parts Discussed in Thread: TPS65988, , TUSB321

Tool/software:

Hi,

I'm wondering to confirm my understanding of the cable orientation for TUSB542 SEL GPIO piloting. I'm using TPS65988 whose document show that PlugOrientation = 0 if upside up (plug CC on C_CC1) and 1 if upside down (plug CC on C_CC2).

And I'm combining with TUSB542 whose cable orientation SEL logic is as following:

So am I right to understand that we need to write "0" to SEL GPIO if PlugOrientation is upside up and "1" if upside down because the polarity of the TPS6988 and TUSB542 are opposite ? Please correct me if I am wrong, there may have confusion in understanding. Thank you in advance

Trang

  • 0
    TI__Mastermind 41130 points

    Hi Trang,

    If CC1 is connected (which I believe indicates TX/RX1), then the SEL pin on the TUSB542 should be high, indicating TX/RX1 should be used. So to me, it sounds like when the TPS6988 PlugOrientation is 0, the TUSB542 needs to be high(1), opposites.

    You may also be able to flip the CC lines to account for this, as opposed to worrying about inverting the signal. The example with the TUSB321 does this for its muxing with the TUSB542:

    Please let me know if that makes sense, if you need more clarification.

    Thanks,

    Ryan 

  • 0 in reply to Ryan Kitto
    Prodigy 35 points

    Hi Ryan,

    Thank you for your reply. Yes effectively CC1 connected indicates TX/RX1. But I'm wondering about the right value to write for USB MUX SEL GPIO (for TUSB542). I found that it is not too clear your documentation of TUSB542 which shows that TUSB542 needs to be opposites of the value TPS65988 PlugOrientation.

    In our hardware schema, there is not any CC lines flipping as image below:

    Could you please show me where in your document shows that TUSB542 needs to be opposites of the value TPS65988 PlugOrientation ? Thank you

    Because in practical, when I wrote "1" to GPIO when TPS65988 PlugOrientation is upside-up, it is not working correctly but "0" it works perfectly. I have verified our hardware schema, there is not any signal inversion. Hence I'm wondering if there is any errata in documentation of TUSB542.

    Best regards,

    Trang

  • 0 in reply to Trang Pham
    TI__Mastermind 41130 points

    Hi Trang,

    We don't have any written down instruction or errata to have opposite values for a CC/PD controller against the TUSB542, that was just my understanding going off of how you described the connection to me. However, if you see a valid USB3 connection when 0 is sent to the TUSB542 when the TPS65988 detects CC1, and when 1 is sent to the TUSB542 when the TPS65988 is detects CC2, then you may not need to inverse the values to match the orientation.

    I can double check and see if we have any previous mention of needing to swap the CC pins or have inverse values from PD/CC controller to TUSB542. Otherwise, if keeping the CC pins to the correct position and outputting 0/1 when CC1 and CC2 are detected respectively works, then I believe that should be fine as well.

    Thanks,

    Ryan