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TUSB212-Q1: Confirm ENA_HS behavior during the handshake process.

Bruce Dai
Intellectual 660 points
Part Number: TUSB212-Q1
Other Parts Discussed in Thread: TUSB212, TUSB216, TUSB211A-Q1, , TUSB216-Q1

Tool/software:

Hi AE,

        I would like to ask for your insight on something.

          

       1. When I reset while keeping H, the USB device works normally, but when I connect a phone, the following issues occur.

          USB Device

       2. What could cause ENA_HS to continuously toggle between H and L?

       3. If the system requires Host/Device role swapping, does the TUSB212 need to be reset accordingly?. 

          

          IPhone

          

         IPhone 2nd piugout Zoom

          

Besr Regards

  • 0
    TI__Mastermind 40965 points

    Hi Bruce,

    Bruce Dai said:
     2. What could cause ENA_HS to continuously toggle between H and L?

    ENA_HS toggling could be due to the signal being overcompensated. Depending on the settings of the TUSB212, if the signal is being overcompensated, then the USB2 connection will disconnect due to the voltage levels of the signals exceeding the disconnect threshold. This could in turn cause the USB2 signal to continually attempt the USB2 handshake process, toggling the ENA_HS pin high and low repeatedly.

    Are you seeing the USB2 redriver able to boost the signal, Or is the signal unboosted? What are the settings for the TUSB212?

    Bruce Dai said:
           3. If the system requires Host/Device role swapping, does the TUSB212 need to be reset accordingly?. 

    No, the TUSB212 should not need to be reset in order to account for role-swapping, as the redriver is host/device agnostic.

    One other thing you could try is using a newer redriver, like the TUSB216, and seeing if that improves performance, as the TUSB216 has improved performance over the TUSB212.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Intellectual 660 points

    Hi AE,

           Thanks for your the great answer.

           1. When we found the 1st Plug out, the ENA_HS should be low by IC.

               Why does ENA_HS remain high when the device is removed?

               

           2. Performing a reset (RSTN) after plug-out can improve this phenomenon.

                  

          3. But we want to know the reason why ENA_HS does not change its level.

              Or is there any setting that needs attention?

    Best Regards

  • 0 in reply to Bruce Dai
    Intellectual 660 points

    Hi AE,

               2. Performing a reset (RSTN) after plug-out can improve this phenomenon.

                   Is it normal to reset ENA_HS through RST?

               

    Best Regards

  • 0 in reply to Bruce Dai
    TI__Mastermind 40965 points

    Hi Bruce,

    Bruce Dai said:

    1. When we found the 1st Plug out, the ENA_HS should be low by IC.

               Why does ENA_HS remain high when the device is removed?

    ENA_HS should not be staying high after the device is removed. That second plug in/out is the expected behavior. I'm not sure what could be causing this, it could be that the TUSB212 entered a test mode after the first plug-in.

    Bruce Dai said:

       2. Performing a reset (RSTN) after plug-out can improve this phenomenon.

                   Is it normal to reset ENA_HS through RST?

    It is not normal to need to reset the device to reset ENA_HS. It should automatically go low after a device is disconnected.

    Bruce Dai said:

    3. But we want to know the reason why ENA_HS does not change its level.

              Or is there any setting that needs attention?

    As I said before, my belief is that the TUSB212 is entering a form of test mode, which is causing the ENA_HS pin to not disable. My main recommendation would be to check the EQ and DC_BOOST pin and ensure it is not overcompensating the signal.

    Also, can you take an eye diagram or monitor the signal to ensure the signal is being boosted by the redriver? You can do this by monitor the signal when the redriver has RSTN high versus RSTN low.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points
    Hi Ryan,
    This issue was found in our product and would like to correct the waveform that I provided to Bruce and provide more info for this issue.
    The default USB role is host of our product (embedded Host), but it would change to device mode after inserting iPhone to support Apple CarPlay. Then change back to host mode once iPhone is removed.
    However, the status of redriver ENA_HS is correct only when first time inserting iPhone after resetting the redriver, but abnormal ENA_HS status and failed USB communication for further iPhone connection.
    The waveform is captured during iPhone is plug in/out, only success by 1st and 2nd iPhone plug in but failed at 3rd time, besides the 2nd plug in is pass due to resetting the redriver manually before plugging the iPhone.
    This issue could be fixed if give redriver a reset between each iPhone Plug in/out, or connect USB disk to our product next to the iPhone removal.
    Further, this issue would not occur if connect USB disk to our product which our product keeps in Host mode.
    Although there’s a recovery method that reset the redriver for every USB disconnection event. We still would like to know the possibly root cause of this issue. Is this happened due to the Host (iPhone) is removed from the redriver instead of removing the device?
    Thanks,
    Jay.
  • 0 in reply to Jay Lin1
    TI__Mastermind 40965 points

    Hi Jay,

    So you only see this issue when you plug in an IPhone? And plugging in a USB Disk/Flash Drive corrects the error? In that case, I believe the issue does likely stem from disconnecting the IPhone, leaving the USB2 redriver thinking there is still a device connected and leaving it enabled.

    Does a 4th plug-in in this scenario correct this issue, since the 3rd plug-in pulled ENA_HS low? Or is the result the same as the 3rd plug-in?

    One other thing I would recommend, aside from testing lower EQ/DC_BOOST settings, is trying with a newer device, like the TUSB216-Q1 or the TUSB211A-Q1. These devices have improved functionality over the TUSB212-Q1, which may include fixes to improve performance when working with a device mode connection.

    Thanks,

    Ryan

  • 0 in reply to Ryan Kitto
    Prodigy 20 points

    Hi Ryan,

    1. Yes, the issue only be found by the application needs to have USB role swap such as iPhone CarPlay or Android Auto. And yes the error can be fixed by just inserting the USB drive.

    2. The 4th plug-in still fail and the waveform is the same as 3rd plug in since the ENA_HS status still incorrect (H->L switching) at 3rd plug out phase as the waveform attached in last reply.

    3. I'm not sure if TUSB216-Q1 is able to meet our design requirement or not since it doesn't support Device mode described in document SLLA593, and it should be supported due to device SI is one of the test items of CarPlay.

    Thanks,

    Jay.

  • 0 in reply to Jay Lin1
    TI__Mastermind 40965 points

    Hi Jay,

    Jay Lin1 said:
    3. I'm not sure if TUSB216-Q1 is able to meet our design requirement or not since it doesn't support Device mode described in document SLLA593, and it should be supported due to device SI is one of the test items of CarPlay.

    The TUSB216-Q1 should support device test mode. We have completed testing with this device previously with CarPlay, so I believe there shouldn't be any issues with it. This table is also slightly outdated compared to what we have today in terms of devices.

    Thanks,

    Ryan