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TUSB321AI: TUSB321 not detecting cable inversion.

AMARNATH G
Prodigy 245 points
Part Number: TUSB321AI
Other Parts Discussed in Thread: TUSB321

Hi Team,

We are using TUSB321A in one of our projects.

I'm using the TUSB321A as DFP configured according to the spec and the current mode is set to the Default current mode.

I'm using Type-C to Type-A converter.

The problem statement is One way in Type-C is detecting USB3.0 but the other way in Type-C is not able to detect USB3.0.

CC2 is going low to 0.42V (i,e: It is within its Threshold limit) when USB3.0 device connected and DIR pin also going high hence USB3.0 device is detected in terminal.

CC1 is going low to 0.7V(i,e: It is not within its Threshold limit) when USB 3.0 device connected, and the DIR pin is not going low and hence the USB3.0 device is not detected.

Request you to provide us a breakthrough from this.

Hereby attaching the snapshot of the schematic and the scope shots of CC1 & CC2 w.r.t DIR pin for your reference.

Thanks.

  • 0
    TI__Mastermind 30090 points

    Hi Amarnath,

    I see the resistor on VBUS_DET is not populated. The TUSB321 needs a ~900K pullup to the Type-C VBUS on this pin.

    I do not see where the ID pin is connected to. This pin is often used to control a VBUS switch on a Type-C DFP. 

    I have a couple questions to get a better idea of the application:

    1. How do you control the Type-C VBUS? If it is left uncontrolled, there could be issues with orientation detection.

    2. Are you plugging a type-C to A converter into the TUSB321 DFP receptacle, or is the TUSB321 being used in the type-C to A converter?

    Best,

    Shane

  • 0
    TI__Mastermind 30090 points

    Hi Amarnath,

    Were you able to solve the issue? I can answer any questions you still have on the 321.

    Otherwise, I'll mark this as resolved.

    Best,

    Shane