TUSB8020B: TUSB8020B use questions for help.

Andy Liu3

Part Number: TUSB8020B

Hi team,

My customer use our TUSB8020B, which device can simultaneously expand USB2.0 and USB3.0 signals.

When customer use TUSB8020B, On one board the two USB ports under a TUSB8020B hub can only recognize 2.0 devices, but not 3.0 devices, At the same time, their other applications use TUSB8020B are normal can recognize both 2.0 and 3.0 devices.
They replaced the CPU and other devices upstream of this TUSB8020B, and the CPU that has been verified to work normally can still only recognize 2.0 devices after this HUB TUSB8020B.

They scan the USB device in the system, and find

Normal board:

Abnormal board:

At the same time, in the BIOS SETUP, they can also see that the wrong board has a missing hub.

Q1.They can see in the BIOS SETUP that the total number of hubs is greater than the number of hub devices. So in our TUSB8020BIPHPR, are the internal USB3.0 and USB2.0 recognized as two independent HUBs?

Q2.Have we dealt with the loss of only USB 3.0 HUB for this chip before? What are the possible reasons?

Q3.Whether there are related registers to check the working status of the internal USB2.0 and USB3.0 Hub of TUSB8020B?

Please help me on this case, thanks, if you have any deep question can email me wenlong-liu@ti.com

Best regards,

Andy Liu

over 4 years ago

0 JMMN over 4 years ago

TI__Guru 60870 points

Hi Andy,

I don't see the missing hub in the "abnormal board" photo? The results look the same.

A1. Yes, USB 3.0 hubs will report as both a USB 2.0 hub and a USB 3.0 hub. For the TUSB8020B, the PIDs are 8027 and 8025.

A2. Are they seeing boards connect sometimes at USB 3.0, but not consistently? This could be a signal quality issue. Can the customer check that the thermal pas has adequate solder and is well connected? This can cause device issues if not connected properly.

A3. No, there are no status registers on the TUSB8020B.

Regards,

JMMN

0 Andy Liu3 over 4 years ago in reply to JMMN

TI__Intellectual 2500 points

Hi JMMN,

Thanks for your reply.

About A2, I will on site check with customer tomorrow.

Can we think that USB3.0 hub in TUSB8020B is damaged, but the USB2.0 hub is normal, that possibility is very small?

Best regards,

Andy Liu

0 JMMN over 4 years ago in reply to Andy Liu3

TI__Guru 60870 points

Hi Andy,

If there is only one board that does not connect at USB 3.0, it could be damage. Are all their boards failing or just one? Is it consistently failing to connect at USB 3.0?

Regards,

JMMN

0 Andy Liu3 over 4 years ago in reply to JMMN

TI__Intellectual 2500 points

Hi JMMN,

Yes, just one board does not connect at USB 3.0, from the description of customer it is consistently failing to connect at USB 3.0.

Best regard,

Andy Liu

0 JMMN over 4 years ago in reply to Andy Liu3

TI__Guru 60870 points

Hi Andy,

If it is a single board, then it could be damaged or an assembly issue. Can you request the lsusb report with the failing board, the "abnormal" photo above still shows all the hubs.

Regards,

JMMN

0 Andy Liu3 over 4 years ago in reply to JMMN

TI__Intellectual 2500 points

Hi JMMN,

Can you give me your email? I have some new information about this case.

Best regards,

Andy Liu

+1 JMMN over 4 years ago in reply to Andy Liu3

TI__Guru 60870 points

HI Andy,

I'm sending you a friendship request over E2E so we can share emails.

Regards,

JMMN

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TUSB8020B: TUSB8020B use questions for help.