TUSB8041: testing question

CK Ho

Part Number: TUSB8041

Dear sir,

Our customer is using TUSB8041I. They are doing USB3.0 TX eye-diagram test, but the TUSB8041I can only generate CP1 test pattern. It cannot change to other patterns.

Is there something wrong?? or some setting need to be taken care?? (Attachment is the schematic)

Thank you very much for your help.

USB3.0 HUB.pdf

over 7 years ago

0 JMMN over 7 years ago

TI__Guru 60870 points

How is the customer generating the ping LFPS to change compliance patterns? With a function generator or with test equipment?

Regards,
JMMN

0 CK Ho over 7 years ago in reply to JMMN

Expert 1780 points

with test equipment (tektronix oscilloscope)

0 JMMN over 7 years ago in reply to CK Ho

TI__Guru 60870 points

Can you send a photo of the setup? Thanks

0 CK Ho over 7 years ago in reply to JMMN

Expert 1780 points

Dear JMMN,

We found that the HUB will send out the LFPS signal and then turn to send out CP0.

But quickly it turn back to send out LFPS, and then turn to send out CP0 again and again.

Such as below figure. It looks like something resets the HUB constantly.

Do you have any idea or experience about it??

Thank you very much.

0 JMMN over 7 years ago in reply to CK Ho

TI__Guru 60870 points

What is connected upstream of the TUSB8041? Please make sure it is the XHSETT tool from the USB-IF (download from usb.org) is running on the host, regular host controller drivers will attempt to reset the hub when the downstream ports enter compliance mode and cause unexpected behavior.

Regards,
JMMN

0 CK Ho over 7 years ago in reply to JMMN

Expert 1780 points

Dear JMMN,
Thanks for your reply.
But this design is on the Android system, not on the Windows.
The CPU is used NXP i.MAX
How do we use the XHSETT tool?? Is there a Android version of XHSETT??

0 JMMN over 7 years ago in reply to CK Ho

TI__Guru 60870 points

Hi CK,

I'm not aware of an Android version of XHSETT. It may be best to just disable the hub driver during the test to prevent resets.

Regards,
JMMN

0 CK Ho over 7 years ago in reply to JMMN

Expert 1780 points

OK, I will try it.
Thank you very very much.

0 CK Ho over 7 years ago in reply to CK Ho

Expert 1780 points

Dear JMMN,
The USB HUB will not work if we disable the driver.
The upstream of the TUSB8041 is connected to an ARM based processor.
We have no idea how to do the compliance test.
Do you have any experience about it??

0 JMMN over 7 years ago in reply to CK Ho

TI__Guru 60870 points

Hi CK,

Unfortunately, you need to be able to force the USB driver not to reset ports in compliance mode to run the electrical tests. There is no way for a hub to work around a driver that is generating resets during the test.

Regards,
JMMN

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TUSB8041: testing question