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USB-C Socket Issue with USB 3.2 Gen 2x1 vs USB 3.2 Gen 1x2

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  • USB-C Socket Issue with USB 3.2 Gen 2x1 vs USB 3.2 Gen 1x2

    Dear Passmark Team, Dear Forum Community.
    We have faced a very strange issue testing our new developed board with USB 3.2 Gen2 capability. The Board is based on an Intel W480 Chipset and is capable of providing USB 3.2 Gen 1x1 and USB 3.2 Gen 2x1 speed.
    One of the sockets we have designed with USB-C connector.

    When we test the Device USB-A Ports with the Passmark USB 3.0 Loopback Plugs it works well without any issue.
    When we connect the USB 3.0 Loopback Plugs to the USB-C socket, we only get USB 2.0 speed (480Mbps). We tried with many different cables with USB C to the host and USB Micro B to the USB 3.0 Loopback Plug. But no chance to get USB Gen 2x1 (SuperSpeed) 5Gbit/s .

    It seems, that our interface has an issue with especially the USB 3.2 Gen 1x1 SuperSpeed 5Gbit/s protocol.

    However, when we use USB 3.2 Gen 2x1 SuperSpeed+ Devices with 10Gbit/s on the USB-C port, it works without any issue also with different cables and lenght etc.. even up to 3Meter length, which is usually not recommended by many vendors.

    Anyway, I just wanted to know, if someone had similar issues with USB-C interface and perhaps can help us to find the root cause of this topic in order we can change our design.

    Some background on our design:

    USB Host (from the Intel W480E Chpset) is just being linked to 3 USB-A Ports and 1 USB-C port.
    Inbetween the Host and the USB-C port we have integrated an MUX HD3SS3220 from TI, which is necessary due to the USB-C socket.
    As explained before, all USB-A ports works with all Speeds and protocols up the the maximum of USB 3.2 Gen 2x1 10Gbit/s and only on the USB-C we get USB 2.0 and USB 3.2 Gen 2x1 SuperSpeed+, only the USB 3.2 Gen 1x2 is not working.


  • #2

    The USB naming standards are quite confusing and it makes it a little hard for us to understand the board that you are testing exactly sorry. With the only 1 Type-C port on the board (which is the problematic port) is this port a Gen 1x1, Gen 1x2 or Gen 2x1 port and what speed appears on the USB 3.0 Loopback Plug when you plug it into this Type-C port?

    Also, if the Type-A port is working correctly, then we suspect that what may be causing the issue is the cable as some USB-C to Micro B cable don't support USB 3 speeds, although they look identical to a cable that does which makes things confusing. Our USB-C to Micro B cable (product page: does support USB 3 speeds and so if you are using this cable in your test then the issue is not the cable and somewhere else.