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TUSB2077A Downstream port detection failure

POORNAKUMAR A M
Prodigy 160 points
Other Parts Discussed in Thread: TUSB2077A

Hello,

          I have used TUSB2077a to construct a self powered, ganged power management device. The had some issues in device enumeration but got it solved from your support team. The problem I'm facing now is that the device in the Downstream port a HID Keyboard device is connected to port 5 of TUSB but doesn't get detected in the PC. when I use other ready-available USB hubs in the market the same device gets detected.

  • 0
    TI__Mastermind 18655 points

    Hello,

    Is the device permanently attached? 

    You can add 22pF  edge rate control capacitor on the downstream ports, however I think there is some physical issue, check your connections and layout.

    Connect the hub to a different USB host and different downstream devices. 

    Regards,
    Joel 

     

  • 0 in reply to Joel Jimenez0
    Prodigy 160 points
    Yes the device is permanently attached.

    But, I also tried it both ways permanent and partially connected devices to check the problem.
    'The Layout' you mean the PCB Circuit layout ?. I'll also check with some other downstream devices.
  • 0 in reply to POORNAKUMAR A M
    Prodigy 160 points

    Hi Joel,
    The data lines already have edge rate control capacitors on them. I also tried different Downstream port devices and Upstream devices (PC win 7), still the downstream device doesn't get detected. Can you suggest any test case to debug this issue?

    One different case in Layout is that, I have give the PCB layout for connector in sequence of   V+, DP, DM, Gnd   (Standard is V+, DM, DP, Gnd), would this affect the circuitry?

  • 0 in reply to POORNAKUMAR A M
    TI__Mastermind 18655 points

    Hi,

    Just for clarifying, Are you able to see another downstream devices enumerated in your system?
    Check whether the D+ and D- downstream terminal are not physically swapped in the board. Also, check that you have a pull-up resistor in D+ or D- of your downstream port. Full-speed and low-speed devices are differentiated by the position of the pull-up resistor on the downstream end of the cable. Full-speed devices are terminated with the pull-up resistor on the D+ line. Low-speed devices are terminated with the pull-up resistor on the D- line.

    Regards




     


  • 0 in reply to Joel Jimenez0
    Prodigy 160 points

    Hi,
    None of the downstream devices of the hub are listed. the data lines are connected as below.
    In the downstream port of the Hub I have attached a 15 K pull down. But in the Downstream device how do I check that if the D+ / D- is pulled up (using 1.5K). since the downstream device is passive (powered by USB_Hub) and also the hub's downstream ports are not powered until the Downstream device is detected. I checked the resistance b/w V,D+ & V,D- of downstream device using DMM but the resistance values were pointing in Mega ohms.

    I have no idea in what kind of issue I'm facing, please be specific if you could.


    Hub's Downstream port            -          Downstream Device's port
    ----------------------------------                     ---------------------------------------
    V                                                                     V
    D+                                                                  D+
    D-                                                                   D-
    Gnd                                                                Gnd

  • 0 in reply to POORNAKUMAR A M
    TI__Mastermind 18655 points

    Hello,
    After double-checking your schematics, and I noticed that the EXTMEM\ pin is left unconnected, please connect this terminal to Vcc.
    Are you able to send me your schematics with values in the passive components?
    Regards

  • 0 in reply to Joel Jimenez0
    Prodigy 160 points

    Hi,
    I have used the same values for Passive components as proposed in datasheet of TUSB2077A. After your 1st suggestion I have connected EXTMEM pin to Vcc (3.3V) and only then the device was enumerated with ids in the PC. But the downstream devices are not detected when plugged-in. Would this data help to debug?. I feel the Device is not fully configured is my doubt right?!

    From USBView:

    External Hub: USB#VID_0451&PID_2077#6&17017a73&0&5#{f18a0e88-c30c-11d0-8815-00a0c906bed8}
    Hub Power: Self Power
    Number of Ports: 7
    Power switching: Ganged
    Compound device: No
    Over-current Protection: Global

    Extended Hub Capability Flags: 00000000
    High speed Capable: No
    High speed: No
    Mulit-transaction Capable: No
    Mulit-transaction ON: No
    Root hub: No
    Armed for wake on connect: No
    Reserved (26 bits): 000000

    Device Descriptor:
    bcdUSB: 0x0110
    bDeviceClass: 0x09
    bDeviceSubClass: 0x00
    bDeviceProtocol: 0x00
    bMaxPacketSize0: 0x08 (8)
    idVendor: 0x0451 (Texas Instruments)
    idProduct: 0x2077
    bcdDevice: 0x0100
    iManufacturer: 0x00
    iProduct: 0x01
    0x0409: "General Purpose USB Hub"
    0x0409: "General Purpose USB Hub"
    0x0409: "General Purpose USB Hub"
    iSerialNumber: 0x00
    bNumConfigurations: 0x01

    ConnectionStatus: DeviceConnected
    Current Config Value: 0x01
    Device Bus Speed: Full
    Device Address: 0x02
    Open Pipes: 1

    Endpoint Descriptor:
    bEndpointAddress: 0x81 IN
    Transfer Type: Interrupt
    wMaxPacketSize: 0x0001 (1)
    bInterval: 0xFF

    Configuration Descriptor:
    wTotalLength: 0x0019
    bNumInterfaces: 0x01
    bConfigurationValue: 0x01
    iConfiguration: 0x01
    0x0409: "General Purpose USB Hub"
    0x0409: "General Purpose USB Hub"
    0x0409: "General Purpose USB Hub"
    bmAttributes: 0xE0 (Bus Powered Self Powered Remote Wakeup)
    MaxPower: 0x00 (0 mA)

    Interface Descriptor:
    bInterfaceNumber: 0x00
    bAlternateSetting: 0x00
    bNumEndpoints: 0x01
    bInterfaceClass: 0x09 (Hub)
    bInterfaceSubClass: 0x00
    bInterfaceProtocol: 0x00
    iInterface: 0x01
    0x0409: "General Purpose USB Hub"
    0x0409: "General Purpose USB Hub"
    0x0409: "General Purpose USB Hub"

    Endpoint Descriptor:
    bEndpointAddress: 0x81 IN
    Transfer Type: Interrupt
    wMaxPacketSize: 0x0001 (1)
    bInterval: 0xFF

  • 0 in reply to POORNAKUMAR A M
    Prodigy 160 points
    Hello,
    need some help here!..
  • 0 in reply to POORNAKUMAR A M
    TI__Guru* 76130 points
    Please provide your schematic, what does the below table mean? You posted on Dec 15, 11:21 PM

    Hub's Downstream port - Downstream Device's port
    ---------------------------------- ---------------------------------------
    V V
    D+ D+
    D- D-
    Gnd Gnd

    Seems like you have D+/D- swapped.
  • 0 in reply to Elias Villegas M.
    Prodigy 160 points

    Hi Elias,
    Thanks for your reply. sorry for getting back after a long time. Was stuck in redesigning the layout of the PCB (considering any layout issues). But still the same problem persists. Please help me with this issue. my post on the above was ment for how the device is connected to the USB hub's pins. I have shorted the EXTMEM pin to Vcc (3.3 V)

    attached the file:

  • 0 in reply to POORNAKUMAR A M
    TI__Mastermind 18655 points
    Hello,
    Just for clarifying, is your device getting enumerated when is connected to the others downstream ports?
    Regards
  • 0 in reply to Joel Jimenez0
    Prodigy 160 points
    Hi,
    Yes the end device gets connected when its connected to other USB Hubs downstream ports. The issue only happens with the USB hub that we designed with TUSB2077A
  • 0 in reply to POORNAKUMAR A M
    Prodigy 60 points
    Hi POORNAKUMAR,

    Did you able to found any solution for this? I'm also facing the same issue USB HUb is detected but downstream ports are not detected.
  • 0 in reply to Danish Malhotra
    TI__Mastermind 18655 points

    Hello,

    Sorry, I missed this thread. Please, share your schematics.

    Regards

  • 0 in reply to Joel Jimenez0
    Prodigy 60 points

    Hi Joel,

    Please find the schematics.

    Regards,

    DanishUSB_Patch_Panel.pdf

  • 0 in reply to Danish Malhotra
    TI__Mastermind 18655 points
    Hello Danish,

    I cannot see the pull-ups in the OVRCUR terminals. TheTUSB2077A does not have internal pull-up resistors on the OVRCUR/ inputs and these are required (unless the power switch has them implemented internally).

    Regards
  • 0 in reply to Joel Jimenez0
    Prodigy 60 points
    Thank you so much joel. I Pulled up Ovrcur lines with 15K resistor and ports started working. Again thanks for ur help!!!!
  • 0 in reply to Joel Jimenez0
    Prodigy 60 points
    Hello Joel,

    I want one more advice from you. I want to continuosly monitor whether all my ports are working fine or not. How can i achieve that through hardware means through D+ or D- line or any other better way.
  • 0 in reply to Danish Malhotra
    TI__Mastermind 18655 points
    Hello Danish,

    The optimal way to check this is by connecting a device to confirm that the transactions between the USB host and the downstream device are performed correctly.

    Regards