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Questions for using TPS2054 with the TUSB2046, PCM2706 & PCM2900E

Ben Palmer
Prodigy 150 points
Other Parts Discussed in Thread: PCM2706, TPS2044, PCM2900C, TPS2044B, TUSB2046B, TPS2071, PCM2706C, TPS2051, TPS2041

The setup I have is a TUSB2046 hub, connected to qty 3 PCM2706 & qty 1 PCM2900E. I went based off page 15 of the TUSB data sheet schematic: http://www.ti.com/lit/gpn/tusb2046b

I am using the TPS2044, and have the OC pins & EN pins directly connected to the hub, as shown in the schematic. BUT, if you look at the schematics listed on pages 15, 19 & 20, on the TPS2044 data sheet, it shows  a resistor & a 3.3V supply going to the OC pins: www.ti.com/.../getliterature.tsp

1) Should I run 3.3V to the OC Pins?

2) And if so, what resistor value do I put there???

The reason I ask, is because my sound cards are not recognized in Windows. Here's some details:

-Windows recognizes the hub, as a generic hub. So I get the impression that the hub is operating properly.

-The OC pins on the hub/TPS2044 are active low, and the PWRON pins are high. Which I interpret it to be saying that the protection mode has been set and the sound cards have been disabled.

-Both the 2900 & 2706 SSPND pins are low.

-I am running in Bus Powered mode, since I need the 2706 to be able to do custom names, and the only way it can do custom names is if it is bus powered.

-I have the 2706 HOST set to low, so that it is running at 100mA.

-The voltage going to the 2900 pin 3 is 5V, which is good.

-The voltage going to the 2706 pin 24 is only 2.8V.

Thank you for your help! And please let me know if you have any questions. THANKS!!!!

  • 0
    Prodigy 150 points
    Pardon, I meant to say PCM2900C.
  • 0
    TI__Guru* 95335 points
    Hi Ben,

    According to TPS2044B EVM schematic I would say that this device requires pull up resistors on OCx pins, 10K-Ohm should do it. You could ask this to the Power Management team as they are in charge of this device. Perhaps the USB Interface team made a mistake in their TUSB2046B datasheet as there are other devices like TPS2071 that seems to not require these pull up resistors.
    You could try this and see if the board is working now.

    Best regards,
    -Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Prodigy 150 points
    Thank you for the help. That was the issue.

    I have another related question. I want to name the 2706 a different name in the descriptor now. The question is, on page 21 of the datasheet, it looks like I have to have the Host pin 3 set to high in order to have a custom descriptor. But I was under the impression that the Host pin needs to be low, so it only pulls 100mA, so it'll work with the USB hub. Am I able to leave the host pin low or can I put it high? Or am I not able to have a custom descriptor with using the hub? Thanks for your help!
  • 0 in reply to Ben Palmer
    TI__Guru* 95335 points
    Hi Ben,

    For a custom descriptor setting HOST and PSEL must be set high. But you can modify the Max Power descriptor, as described in page 23 from PCM2706C datasheet.

    Best regards,
    -Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Prodigy 150 points
    Perfect! That's what I figured. I'll program it to the 0x32 setting for 100mA. Thanks!!!
  • 0 in reply to Ben Palmer
    Prodigy 150 points
    Hello Ivan,
    We have a different, but probably related problem.
    So we ultimately figured out our previous problem by powering the custom EEPROM from the PCM2706C pin 2. We were originally powering the EEPROM direct.

    We are using the TUSB 2046B Hub, and have it connected to qty 3 of the PCM2706C DAC's. The 4th is a CODEC, PCM2900CDB. When the computer is already on, and we power up the sound cards, everything comes up properly. We have 3 custom names for the 2706, and the USB Audio Codec 2900 comes up properly as well. Everything works great.

    BUT, when I power the computer down, leaving the sound cards still powered on, and then turn the PC on again, it does not recognize the qty 3 2706 sound cards. It does however recognize the USB Audio Codec 2900. When I reset the power on the sound cards, everything comes up proper and works again.

    Any ideas of what is different for when the PC is turned on, and it doesn't recognize the sound cards on power up? We have tested it on a handful of PC's, with Windows OS7, 8 and 10. All the same results.

    Thank you very much for your help!
  • 0 in reply to Ben Palmer
    TI__Guru* 95335 points
    Hi Ben,

    This sounds to me like a problem with the EEPROM descriptors. Perhaps there need to be a read back of the descriptors from the EEPROM when the PC is turned on.
    Doing a reset of the power on the sound cards makes the PCM2706C to perform the read of the EEPROM to report back to the host.
    PCM2706C may need to be reset every time it is connected to the host. D+ pull up resistor is active when the host is not connected? There is a note on data sheet page 35 that may explain this behavior:
    (3) D+ pullup must not be activated (high: 3.3 V) while the device is detached from USB or power supply is not applied on VDD and VCCx.
    VBUS of USB (5 V) can be used to detect USB power status.

    Best regards,
    -Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Prodigy 150 points
    Hi Ivan,

    I think you're right, and that is the source of the problem. It is active high on the D+ pullup when the computer is turned on, so it doesn't pull the naming.

    At the moment, I am following the schematic on page 15 of the TUSB2046B datasheet. (www.google.com/url

    The D+ going to the PCM2706C is supplied from the TUSB2046B. And the VBUS on pin 24 of the PCM2706B is coming from the TPS2044 as listed on the TUSB2046B schematic. So unless I power down the TUSB2046B, and then power it up, it will always keep that D+ on the PCM2706B high.

    At the moment, I have Pin 8 (BUSPWR) pulled low on the TUSB2046B. I assume that that is correct? I also don't have the +5V on the Upstream Port connected, as shown on page 15 of the TUSB2046B schematic.

    So I guess the next questions are, is there a way to connect the USB +5V to the TUSB2046B, so that it knows when to supply power to the downstream ports? OR is there a way to reset the hub on PC power up?

    Thank you for your help!!!
  • 0 in reply to Ben Palmer
    Prodigy 150 points

    Hi again,

    Do you have a schematic that you would recommend following? I feel like I have tried every combination, and can't get it to work upon reset / power cycle. I am using the TUSB2046B hub with the PCM2706. The power management is using the TPS2044 & TPS2051. I have the TPS2051 EN pin going to the 5V on the USB line. I then have incoming 5V from my power supply going to the IN on the TPS2051, and then the OUT pin on the TPS2051 going to the 5V input on my voltage regulator. I then have the 3.3V going to the VCC on the TUSB2046B. And I also have the 5V going to the inputs on the TPS2044. The EN & OC pins from the TPS2044 connect ot the PWRON & OVRCUR Pins on the TUSB2046B.

    Do you have a schematic that you would recommend using for all this?

    One other thing I noticed on the TPS2044 datasheet, on page 22, it shows the BUSPWR pin on the TUSB2040 going to the TPS2041 EN pin. I didn't connect that one. Should I??? The BUSPWR pin on the TUSB2046B datasheet says that it is either high or low, and that it shouldn't change dynamically. At the moment, I only have the BUSPWR set to low.

    Please help!

    Thanks!

    Ben

  • 0 in reply to Ivan Salazar
    Prodigy 150 points

    Hi again,

    Not sure if it helps, but when I reboot the PC, I get the error message 'Insufficient system resources exist to complete the API.' Here's the steps I take to get this problem:

    1) Power up the PC, connect the sound card hub, and everything comes up properly, and named.

    2) Power down the PC with the sound card hub powered and connected to the PC.

    3) Power up the PC with the sound card hub powered and connected. Now it won't recognize the custom dac name or USB, and give that above error message.

    4) IF I now disconnect the USB, or restart the USB sound card hub, it will come up properly once more.

    So... What do I need to do to get it to come up properly on boot?

    Thanks!

    Ben

  • 0 in reply to Ivan Salazar
    Prodigy 150 points
    Hi Ivan,
    So here's probably some better clues as to what is happening. Looking at your comment:
    "(3) D+ pullup must not be activated (high: 3.3 V) while the device is detached from USB or power supply is not applied on VDD and VCCx.
    VBUS of USB (5 V) can be used to detect USB power status."
    This got me looking closer at that. When the USB is connected, it goes to 3V. When the USB is disconnected, it goes to ~2.3V. Is this not dropping enough? If so, how do I drop it down more? This voltage seems to be originating from the DP1 on the TUSB hub. I have the 27ohm series resistor there, as it asks for on the TUSB datasheet. I haven't added the filter cap yet, but will try that tomorrow.
    Any additional thoughts will be appreciated.

    Thanks!