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Original question:

TUSB2046B: USB Hub does not get recognised

TUSB2046B: Hub not recognized, schematic issue?

ANDREW DEMEDEIROS
Prodigy 70 points
Part Number: TUSB2046B

Hi All,

Have a design using the TUSB2046BIRHBT which isnt working. Have gone through the checklist a few times and nothing jumps out at me. 

Crystal input on XTAL1/2 seems correct at 6MHZ, 3Vpp. I do not see any toggling of DM or DP on pins 1/2. Wondering if there is some schematic issue that I have overlooked. Any help would be greatly appreciated.

Thanks!USBSwitchSchematic.pdf

  • 0
    Prodigy 70 points

    As a follow up, I realized right after posting the initial question that my design omitted the 1.5K pullup on DP. Added the resistor and Windows now appears to at least see the device, however I am getting the following error.  I am able to access data on the downstream ports however, using a USB drive.

    I have modified the reset circuit (TPS3840PL30DBVRQ1) to have a 1uF external capacitor, which gives me a delay of approximately 680mS after power on.

  • +1 in reply to ANDREW DEMEDEIROS
    Prodigy 70 points

    Issues have been corrected. Determined that I omitted the 15k pull downs as well as the 1.5K pull up resistors. After replacing those, things seem to be ok.