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Original question:

TUSB2077A: TUSB2077A only recognized as USB1.1 hub

TUSB2077A: HUB in Windows10 recognized as HUB1.1 and ports UNUSED with OC. Some devices not being recognized and not working.

Hector Martinez
Prodigy 20 points
Part Number: TUSB2077A
Other Parts Discussed in Thread: TUSB2036, TUSB4041I

Hello,

I'm Hector and I've been working in a personalized HUB design with 5 ports used. 4 of them with USB Type A connectors and 1 USB embedded in PCB design connected to a STM32 USB pins.

I'm using self powered hub with external 5V power supply and 3.3V.

I've connected some devices as: Iphone Xr, Digital Microscope USB, several HDD drives, a KINDLE and all of them were recognized and working well.

Later I connected 4 different cameras: 2 INTEL realsense D400 series and 2 cameras HD USB 2.0. and were not working or being recognized well.

I used as reference "TUSB2036 and TUSB2077A EVM User's Guide" BOARDS and also with the proper datasheet to design customized.

Using software "USB Device Tree Viewer", I could notice that the HUB was being detected in windows10 as HUB1.1 letting me know that there was a problem as not being recognized as 2.0 but still working with some devices. I follow up layout design guidelines and recommendations. 

I also noticed that in LED indicators as in EVM boards, the PORTPWR was RED LED, meaning all ports are off, but when I connected the working devices I mentioned, it was still red led. Check design and was properly connected. Also it is supposed to be only powered ON (PWRON1-7(NEG) active low) when a device is connected no? Well all were low meaning the green leds of the 5 ports when any port was ON. The GANGED PIN is in set in HIGH, so it should be controlled individually.

I'm using also 6 MHz clock, is this a reason for not being able to work in HIGH-SPEED (USB 2.0)? It is supposed to use 6-MHz from which internal APLL circuitry generates a 48-MHz internal clock to sample the data from the upstream port.

What I haven't done is that 2 unused ports (PORT 6 & 7) I left pins floating, maybe it is causing some noise to the IC so it can be 2.0? Or is there something I missed in my design?

I attached schematics. If PCB layout needed let me know.

Please help, I would appreciate it.

Thanks in advance.

Héctor.

hmartinez@kybel.mx

usbhub5ports.pdf

  • 0
    TI__Guru 60870 points

    HI Hector,

    The TUSB2077A is a Full Speed hub, so it is only capable of 12 Mbps.  Cameras will likely have difficulty operating at those speeds.

    The downstream port power of the hub is controlled by the USB host controller.  The port power is turned on / off depending on the USB commands received from the host, most hosts turn on / off all ports at the same time.  Although, if the hub is set up as individually controlled, the hub can power on/off ports individually if it receives the proper commands from the USB host.

    Unused ports should be pulled low to prevent false connect events, but that does not appear to be causing the issues you are reporting.

    Does PORTPWR ever go high?  Do HUBCFG and PORTDIS LEDs work properly?

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 20 points

    Hello JMMN,

    Thanks for the fast reply,

    So, if it is only capable of 12 Mbps, shouldn't be named  a 1.1HUB why in the datasheet description says it's a Device  with 7 ports in compliance with the USB 2.0 specification? Or am I misunderstanding the type of HUB it is? 

    Yes, unused ports are only showing as OC ports but the other ones no problem when connecting some devices.

    PORTPWR haven't seen it going high, but HUBCFG and PORTDIS LEDs are working properly (GREEN LEDs ON). When connecting ONE CAMERA USB 2.0 PORTDIS LED Toggles: 99% green led on, 1% red led on aproximate. When connecting 2 cameras USB 2.0, PORTDIS keep in RED LED ON. 

    If Full-speed hub is a problem for this types of cameras, should I consider going with another IC HUB? AND if Yes, which can be the most compatible HUB for this types of cameras? Also if there's an IC pin compatible with TUSB2077A 48-LQFP that maybe almost imposible but anyway asking...

    Thank you,

    Regards,

    Hector.

  • +1 in reply to Hector Martinez
    TI__Guru 60870 points

    Hi Hector,

    While it is common to use USB 1.1 to denote FS/LS and USB 2.0 to denote HS operation, USB 2.0 is a revision to the USB 1.1 specification so any FS/LS device released after the USB 2.0 spec released would be considered USB 2.0 Full speed or Low speed devices.

    When you say that the "unused ports are only showing as OC ports" do you mean that they are reporting overcurrent conditions?  The OVERCUR6 and OVERCUR7 pins can be tied together and pulled high to prevent that.  The false overcurrent event reporting may be causing the problems with PORTPWR LED.

    What is reported on the host when you connect two cameras?  Are you getting any bandwidth errors or power errors?  How much current does your design supply to the downstream ports on VBUS?  I would expect both the camera to enumerate properly but for operation to possibly be choppy or slow.

    We don't have a pin 2 pin USB 2.0 High Speed hub, our closest is the TUSB4041I which is a 4 port USB 2.0 HS hub.

    Regards,

    JMMN