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TUSB8041: USB2.0 Compliance Test Issue

Darren (FAE)
Expert 5483 points

Part Number: TUSB8041
Other Parts Discussed in Thread: TUSB213,

I have a customer using the TUSB8041 device in one of their designs, and we are seeing two problems during compliance testing.

1. EL_17 Receiver Sensitivity Test - FAILS
The EL_17 Hub Receiver Sensitivity Test (part of the upstream-side USB2.0 Rx Compliance Testing) fails on two separate boards.
- A board designed by the customer using the TUSB8041I & TUSB213(Redriver)
- Our TUSB8041 EVM

I have some documentation/waveforms I can send offline (not for online sharing), showing the measurement results w/ our EVM.
It looks like there is about 120mV of DC offset applied to the USB2.0 signals.

Q1: Do we have any test results showing results of the USB2.0 Hub Receiver Sensitivity testing - or can this be performed?
Q2: Is there any reason this could be happening (let's start with the TUSB8041 EVM)

2. The TUSB8041 + TUSB213 board sometimes fails to even enter compliance mode
There are multiple boards (customer design) with the TUSB8041 and TUSB213 - some boards enter compliance mode, some do not.
For our TUSB8041 EVM - it enters compliance mode

Q3: Is there any chance TUSB213 could affect entry into compliance mode? If so, how?

  • 0
    TI__Guru 60870 points

    Hi Darren,

    1.  TUSB8041EVM was the same board / silicon that was verified in our lab and also sent to a 3rd party test house for USB-IF compliance testing.  It should pass EL-17 without issue.  I will send you a direct email so you can send the waveforms.  There should be no offset.

    2. Depending on the test procedure, the redriver may be exiting HS active or compliance test mode.  Can you share information on the test setup / test steps?  I would assume that the 213 is on the upstream port of the hub.  The host is connected to the upstream port of the hub through a test fixture.  The test tool on the host is used to place the hub in TEST_SE0_NAK mode and then the switch is toggled on the test fixture so the signal generator starts sending packets to the hub.  Is that correct?  Can you confirm that VBUS to the upstream port of the hub stays enabled throughout the test?  Is the signal generator sending packets before the switch on the test fixture is toggled?

    Thanks,

    JMMN

  • 0 in reply to JMMN
    TI__Guru 60870 points

    Hi Darren,

    A1: This looks like a test setup issue on the pattern generator.  The packets in the test report are not from the hub, since it is a receiver test, they are the packets from the pattern generator.    

    Let me know when you have more information on the customer test setup.

    Regards,

    JMMN