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OMAP3530 can not enumerate usb devices without a usb-hub

Simon Cool
Intellectual 340 points
Other Parts Discussed in Thread: OMAP3530

I set omap3530 usb host  to usb serial mode and connect the usb port2 with a 4-pin usb transceiver. 

Now omap3530 can accept a usb hub successfully and can accept usb devices through usb hub.  But omap3530 failed to accept usb devices without usb hub.

I know that a usb hub is needed to accept FS/LS devices when the OMAP3530 is using ULPI.

Do we also have to use a hub in OHCI mode?

 

The following log is printed when I connect a usb disk to omap3530:

<7>ohci-omap3 ohci-omap3.0: auto-wakeup root hub
<7>hub 1-0:1.0: state 7 ports 3 chg 0000 evt 0004
<7>ohci-omap3 ohci-omap3.0: GetStatus roothub.portstatus [1] = 0x00010101 CSC PPS CCS
<7>hub 1-0:1.0: port 2, status 0101, change 0001, 12 Mb/s
<7>hub 1-0:1.0: debounce: port 2: total 100ms stable 100ms status 0x101
<7>ohci-omap3 ohci-omap3.0: GetStatus roothub.portstatus [1] = 0x00130301 PRSC PESC CSC LSDA PPS CCS
<3>hub 1-0:1.0: unable to enumerate USB device on port 2

 

  • 0
    TI__Genius 9460 points

    FS/LS devices should work directly without a hub in OHCI mode. Do you see a valid Vbus on USB ? I am thinking if Vbus is not enough but is available with hub connected.

    Ajay

  • 0 in reply to Ajay
    TI__Guru 63145 points

    Are you still having a problem enumerating USB devices not connected through a hub?  If so, did you use a self powered or bus powered hub?  The schematic you sent me had the 4-wire serial transceiver connected to an on-board USB device.  Since the on-board device is being powered by a on-board power source the VBUS power source is not needed, but it would be needed if you are trying to connect bus powered USB devices to the serial transceiver.  How are you connecting the USB devices to your board and who is providing VBUS?

     

    Regards,

    Paul

  • 0 in reply to Ajay
    Intellectual 340 points

    Ajay said:

    FS/LS devices should work directly without a hub in OHCI mode. Do you see a valid Vbus on USB ? I am thinking if Vbus is not enough but is available with hub connected.

    Ajay

     

    Hi Ajay, thanks for your reply.

    The VBus is supplied by our board and it is 4.79V. I have tried to increase the supply to 5V but has no change. 

  • 0 in reply to peaves
    Intellectual 340 points

    peaves said:
    Are you still having a problem enumerating USB devices not connected through a hub?  If so, did you use a self powered or bus powered hub?  The schematic you sent me had the 4-wire serial transceiver connected to an on-board USB device.  Since the on-board device is being powered by a on-board power source the VBUS power source is not needed, but it would be needed if you are trying to connect bus powered USB devices to the serial transceiver.  How are you connecting the USB devices to your board and who is providing VBUS?
     
    Regards,
    Paul

     

    Hi , Paul

        Yes ,that is a self-powered hub.  The VBus is powered by our board with 5V.  

      I am a little confused that the powered hub is more than a usb device?    What's the special?

  • 0 in reply to Simon Cool
    TI__Guru 63145 points

    You said the hub was self powered and you said VBUS is powered by your board.  I am confused by this reply. 

    A self powered hub is a hub that is powered from its own dedicated power supply.  A bus powered hub is a hub that is powered from the upstream USB port.

    If you were using a self powered hub with its own didicated power source, have you tried to use the same hub operating in bus powered mode by removing its power souce?

     

    Regards,

    Paul

  • 0 in reply to peaves
    Intellectual 340 points

    peaves said:

    You said the hub was self powered and you said VBUS is powered by your board.  I am confused by this reply. 

    A self powered hub is a hub that is powered from its own dedicated power supply.  A bus powered hub is a hub that is powered from the upstream USB port.

    If you were using a self powered hub with its own didicated power source, have you tried to use the same hub operating in bus powered mode by removing its power souce?

     

    Regards,

    Paul

     

    Hi Paul,

      I am sorry for my poor english. What I mean is that:  the usb transceiver has 4 pins: D+,D-,GND,VBUS.  And  we connect the VBus to 5V.  

    The hub which is connected to the usb transceiver has its own power.

  • 0 in reply to Simon Cool
    Intellectual 340 points

    The problem is solved by adding a resistance(80K) at D+ .

    Now usb host can accept any device  ^_^