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TUSB2046B: USBView downstream devices not connected

ROHIT GARG
Prodigy 120 points
Part Number: TUSB2046B

Hi,

I have been testing the TUSB2046 with a custom PCB. I am using only 2 downstream devices.

However, the downstream devices do not seem to be detected/connected.

I have attached the USBView screenshots.

 

Why does the viewer say that the downstream device supports only USB 1.1? Also why is the connection status 'no device connected'?

I have connected the device and I have supplied 5V on the VBUS. The downstream device DP line is high. 

I have attached the schematic. 6471.TUSB2046_test.pdf

Please help,

Thanks

  • 0
    TI__Guru 60870 points

    The TUSB2046B is a USB 2.0 hub (Full Speed), so it can only support Full-Speed or Low-Speed devices. Any USB high-speed device will be supported at Full-speed data rates. The TUSB2046 does not see any downstream device connected on the ports. Can you confirm that the overcurrent inputs are not shorted? Do you see any toggling on the downstream DP/DM lines before DP goes high? Have you tried disconnecting and reconnecting the downstream devices?

    Regards,
    JMMN

  • 0 in reply to JMMN
    Prodigy 120 points

    "The TUSB2046B is a USB 1.1 hub (Full Speed), so it can only support USB 1.1 devices."

    Sorry can you clarify this? The IC description reads: "4-port USB 2.0 12Mbps USB Full-Speed Hub"

    Can it support the FTR232 as a downstream device?

    I have infact shorted the overcurrent pins(pulled them high), as shown in reference schematic here:  

    I have disconnected and reconnected downstream devices.

    Please help,

    Thanks

  • 0 in reply to ROHIT GARG
    TI__Guru 60870 points
    Let me revise my earlier statement. It has become common to use the USB specification names and the device speeds interchangeably where USB 1.1 means Full-Speed and USB 2.0 means High-Speed, but they are not always the same.

    The TUSB2046 is a USB 2.0 Full-Speed (12 Mps) Hub. It can support any USB 2.0 or USB 1.1 Full-Speed or Low-Speed devices. Also, it can support USB 2.0 High-Speed devices, but they will only transfer data at Full-Speed rates. The FTR232 device should work behind the TUSB2046B.

    Do you have the ability to check the DP/DM lines for signalling?