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I try to utilize the TUSB2036 USB hub IC. my hookup/connection is shown below:

schematic

simulate this circuit – Schematic created using CircuitLab

On the above setup, if I plug in a mouse or keyboard on the downstream ports they work as normal (I can move my mouse or write with my keyboard), but if I plug anything else (camera, usb flash drive, another usb hub, microphone, hard drive) I always hear the window's "connected" sound, but then the device does not work as intended (for example I dont see the contents of the USB flash drive). I see this on the device manager:

TUSB downstream not working

I can think of two things:

  1. My hookup is wrong. But how come mouses and keyoards can communicate?
  2. My hookup is correct, but this USB hub IC does not "encode/translate" the data coming from downstreams, and I need to write my own code/middleware to connect to the downstream devices. And the reason I can use the mouse/keyboard is becouse they use a simplified USB communication protocol that does not need to be "encoded/translated" and windows can read it as it is. But this is not mentioned in the datasheet of the IC.

I am about to abandon this IC and use another USB hub IC, but I thought I would ask here for a second opinion.

TUSB not working

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    \$\begingroup\$ Best guess, your mouse or keyboard is happy at USB 1 speeds and does not care much about your wiring. Everything else us USB 2 or higher speeds and the impedance mismatch with your loose cables degrades the signal integrity too far beyond USB (2) specifications. \$\endgroup\$
    – winny
    Jun 16, 2022 at 10:33

1 Answer 1

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The datasheet qualifies the TUSB2036 as "full speed" hub, which is USB 1.1 (1.2 MBit/s)

There is no bug in your circuit and no software will make a high speed hub out of it. It is just doing what it's made for.

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  • \$\begingroup\$ But it also says: "The TUSB2036 hub is a 3.3-V CMOS device that provides up to three downstream ports in compliance with the USB 2.0 specification", at page 1 of the datasheet. So its a usb 2.0 Hub with speeds of a USB 1.1? \$\endgroup\$ Jun 17, 2022 at 7:26
  • \$\begingroup\$ Being compliant with the standard means that it will respond properly when an upstream port attempts to switch it up to full speed. So it doesn't stop working just because it was connected to a USB2.0 system. And USB 2.0 provides for running downstream devices at their lower speeds. \$\endgroup\$
    – gbarry
    Nov 12, 2022 at 6:58

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