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ISOUSB111DWXEVM: Communication issue of ISOUSB111 on MAC.

Yiangos Yiangou
Prodigy 10 points

Part Number: ISOUSB111DWXEVM

Hello.

I am using a ISOUSB111DWX to isolate a full speed usb signal to an STM32F446.

I am observing some very werid behavior where to communication can be established correctly on windows hosts and NOT on mac hosts.

If I use an external USB HUB between the MAC host and the device, I can establish connection but without it I cannot.

Do you have any advice? I can share design files over email.

 

Cheers

  • 0
    TI__Genius 16360 points

    Hi Yiangos,

    Thanks for reaching out.

    Just for clarity, when you say MAC - you mean the Apple MacBook, right?

    Regards
    Varun

  • 0 in reply to Yiangos Yiangou
    TI__Genius 16360 points

    Hi Yiangos,

    Thanks for the confirmation.

    It is indeed very weird to know this. We have also not heard of such an issue before.

    From all the inputs that you have shared above, it definitely looks like a dependency on MAC's internal USB drivers - which unfortunately is something we cannot change and also is not feasible to debug by opening the mac.

    For the windows PC vs MAC scenario - Can you check if the USB drivers spec is exactly the same or different between the two?

    Regards
    Varun

  • 0
    Prodigy 10 points

    Let me try and find that out.

    I am wondering if the MAC has some more tight skew rate or other timing requirement that is more tight than the PC. If I can capture the dataline trace would that be able to help?

  • 0 in reply to Yiangos Yiangou
    TI__Genius 16360 points

    Hi Yiangos,

    Unfortunately, I can't comment on anything with respect to MAC internal timings.

    Ideally, the USB timing requirements are governed by the USB-IF standard. Please note that, ISOUSB is a USB2.0 compliant device and meets every 

    Yiangos Yiangou said:
    If I can capture the dataline trace would that be able to help?

    I'm not really sure if we can do anything about the MAC, but a waveform comparison between a working setup vs non-working setup can definitely help to see and understand what might be causing the communication failure.

    Just remind me - this issue with MAC is 100% repeatable, correct? It's not random in nature, right?

    Regards
    Varun