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TUSB2077A - Downstream Device problem

damjan.mujagic
Prodigy 20 points
Other Parts Discussed in Thread: TUSB2077A

Hello,

i hope You can help me with this.

USB HUB TUSB2077A is configured as :

- Self-Powered ( /BUSPWR == VCC )

- No EEPROM ( /EXTMEM == VCC )

- GANDGED-PORT enabled ( EEDATA/GANGED == GND )

- RESET ( Power-Up )is imlemented with PIC uC.

Enumeration and configuration of USB HUB is successful. In device manager USB Hub is listed Generc USB Hub. SEE image.

I followed your datasheet and connect pull-down 15k resistors on lines DP1,DM1 and 22p Capacitors.0

What can be a problem?

have a nice day,

Damjan 

  • 0
    TI__Guru* 76130 points

    Hello Damjan,

    What is the specific problem that you are facing?

    From your post I can only conclude that the hub is being enumerated correctly.

    Regards.

  • 0 in reply to Elias Villegas M.
    Prodigy 20 points

    Hello Elias,

    let say that you want to connect USB mouse to PC over USB Hub (TUSB2077A) on port DP1 and DM1 or DPx and DMx .. when connected to usb hub sound is played in Windows 7 and message box appeare that device is not recognized ( i tried differend usb devices ). Is there maybe problem in TUSB2077A? All the capacitors and resistors are placed as in datasheet.

    USB HUB is enumerated as should be but problem is in devices connected to USB HUB.

    Regards,

    Damjan

  • 0 in reply to damjan.mujagic
    TI__Guru* 76130 points

    Hello Damjan,

    Can you share your schematics? If you do not want to post them here you can send them to elias.villegas@ti.com

    Are you configuring the hub as a self-powered or bus-powered?

    Is the downstream device self or bus powered?

    Does the failure occur on every downstream port of the hub?

    Do you have passive components in the downstream connection? (22pF cap to gnd, 33ohm series resistor, 15K pull-down)

    Regards.