TUSB4041I: Power up sequence TUSB4041

Hi Frank:

  what is difference between two waveforms? good device vs damaged device? 

  Was  PWRCTL1/BATEN1 pulled up?

Best

Brian

Hi Brian, I'm struggling myself here as well. Vishesh is involved from the beginning.

From what I understand all the waveforms are from non correct starting up cases, just additional tests, the latter though is from a different board. The BATEND1 is externally pulled up, see also Thread 654614 which is "part 1" of this issue (got closed as customer had prio change and came back after almost 8wks).

See again partial schematic, which is all I got.

Hi Frank,

Is the schematic the same across the 2 boards? Is it possible the PWRCTL_POL is pulled down on the second board?

There is a delay while the USB hub is initializing after sampling all the input pins. 

We tested this and see a delay of approx. 260ms after GRSTz is set. PWRCTL_POL = H. This delay will vary from hub to hub. 

Is the customer able to capture a longer waveform, to see if PWRCTL gets pulled up?

Hi Vishesh,

The customer did provide longer waveform, the latest waveform (under point 4) shows 500ms after power-up.

Hi Frank & Vishesh,

PWRCTL_POL is pulled up to +3.3V and so are the PWRCTL1/BATEN1 thru PWRCTL4/BATEN4. The only reason these four signals are low after the reset is that the device is not initialized poperly.

Thanks.

Regards,

Vijay

Hi Frank & Vishesh,

Here is an expanded schematic of the TUSB4041. 

Hi Vijaya;

    Where is  5V-ISO coming from? PWRCTL pin will not be enabled until Vbus is detected from USB_VBus pin (pin 16),

   Can you take waveform with 5V-ISO together? Can  you take waveform for port2 as well to compare?

Best

Brian

Hi Brian,

+5V-ISO comes from a TPS54302 switching regulator. See the schematics below. This feeds the +3.3V-ISO LDO, so +5V-ISO comes up ahead of +3.3V power.

I had a little problem with the board I was working with. Once I identify and fix that problem, I would be glad to send you what you asked for.

Thanks.

Regards,

Vijay 

Got it, please make sure all data took in future using LDO with 500ma.

Best

brian

Hi Brian,

Yes, the +1.1V LDO has been upgraded to 500mA already. I will upgrade the +3.3V LDO to 500mA as well.

Thanks.

Regards,

Vijay

waveform from customer:

Hi Vijaya;

  Did host detect TUSB4041 as HS USB2 hub?

Regards

Brian

Hi Brian,

I haven't even gotten to the point of trying to communicate with the HUB over the USB lines. I am still struggling to have this device initialize properly so it can enable the +5V power through the power switches. I tried using bench power supplies for +3.3V and +1.1V and I cannot get the device to leave the BATEN1-BATEN4 lines in logic high state. It is pulling them low at the end of reset cycle.

I tried this on several boards so far and I am getting the feeling that there is something I am missing.

thanks.

Regarrds,

Vijay

Hi Brian,

I am losing confidence in TUSB4041. We haven't even gotten to the USB communications yet. My understanding is that the device initializes the BATEN1-4 signals based on whether these signals pulled up/pulled down at the end of the reset procedure. These signals are pulled up to +3.3V and at the end of the reset procedure they are pulled down by the TUSB4041. The maximum voltage of these signals is 2.6V during the reset process. Not sure why the signal levels are at 2.6V when they are pulled up to +3.3V.

Also, if the +1.1V is not provided, these signals stay up at +3.3V. I assume the device is not initialized since the core voltage is absent.

Do I need to write to the internal registers to set them to the way I want? I was under the impression that the device set the outputs based on some input signals during the reset process. 

What do you recommend I try?

Thanks.

-Vijay

Hi Brian,

I got hold of the TUSB4041PAPEVM board. I am exercising the BATEN1-4 control signals and the +5V output. As I turn on power on and off, BATEN1-4 don't always come up in the logic high state and likewise +5V output power is not always there at the USB connectors. I do not understand this behavior. Very odd.

Any suggestions? I expect the BATEN1-4 to always come up in the logic high state because that is how they are configured. I also expect to see +5V power at the USB connectors.

Thanks.

Regards,

-Vijay

Hi Vijay:

   I just confirmed on EVM, PWRCTLx will keep low after power on reset until hub upstream port is enumerated successfully. So you need to make sure host can detect TUSB4041 first..

  There is another device ISOUSB111 between host and TUSB4041. If host can not detect TUSB4041, maybe there was an issue between ISOUSB111 and TUSB4041.

  Regarding TUSB4041EVM, did you connect upstream port to a working PC port or laptop port. It should work as expected.

  Where are you located? Can you ask Frank to setup a call?

Regards

Brian

Hi Brian,

I am sorry, I am not following. My understanding is that the TUSB4041 enables the +5V power on all the ports by enabling the power switches on deassertion of the Reset procedure by default. We are not even talking about trying to communicate with the device over the USB lines. Yes, there is a 5kVrms optical device between the upstream port and the TUSB4041.

I just want to make sure we are working on the right issue. I am expecting TUSB4041 to enable the +5V power on all 4 ports upon powerup by leaving the BATEN1-4 signals pulled up. As shown in the power on sequence waveforms, the device is pulling these lines low at the end of the reset procedure. 

I am in Andover, Massachusetts.

Thanks.

Regards,

Vijay

Let's have a call today.

Regards

Brian

Frank is trying to arrange a meeting. I assume you were not available this morning's meeting.

-Vijay

Hi Brian,

Do you want to setup a Teams meeting? I am available now.

Thanks.

Vijay

Had call with Vijya, he will connect hub upstream port to host and test again.

Best

Brian

Hi Vijaya:

  Any test result for your own board?

Best

Brian