TUSB212: HS Signal quality fail - Eye shows rise time issue.

vetrivel prakasam

Prodigy 90 points

Part Number: TUSB212

Hi,

I am using TUSB212 for my HUB board and facing eye diagram failure.

My USB2.0 path has 2 muxes and one board to board connector.

Also attached Eye diagram for your reference.

Re-driver settings:

AC boost settings is maximum ( AC boost level = 3 -Did not mount any resistor on EQ)

DC boost settings is low ( Mid boost - 44K resistor on DC boost/ENS_HS pin)

Questions:

1) I want to slightly increase AC boost from AC boost level 3 ? if so Please share me the resistor value .

2) what will happen if 10K is applied on EQ pin ? will rise time improve further ?

3) What will be maximum value of resistance that we can apply on EQ pin for maximum EQ level for this IC Not meant for level3 ?

4) Why electrical characteristics table shows 6K resistor as minimum for AC boost level 3 and telling DNI on table for the same reason?

Regards

P.Vetrivel

over 6 years ago

0 vetrivel prakasam over 6 years ago

Prodigy 90 points

Hi,

One more data point,

I did the DC boost to mid level with AC boost level 3 , then i don't see the enumeration and sometimes not stable.

Mid level DC boost means leaving DC boost pin floating.

Please let me know how to resolve this issue .

Regards

P.Vetrivel

0 David (ASIC) Liu over 6 years ago in reply to vetrivel prakasam

TI__Guru**** 179776 points

Prakasam

Would you please share your schematic/layout, and do you have the eye diagram without TUSB212?

Thanks
David

0 vetrivel prakasam over 6 years ago in reply to David (ASIC) Liu

Prodigy 90 points

Redriver debug.xlsx MUX CIRCUIT.pdfDavid,

Please find the eye diagram without TUSB212, Schematic and various experiments by different AC/DC boost.

Is it possible to assign FAE to visit Cypress bangalore office?

Regards

P. Vetrivel

0 David (ASIC) Liu over 6 years ago in reply to vetrivel prakasam

TI__Guru**** 179776 points

Prakasam

Who is generating the test packet? Is the host generating the test packet and then propagate through the hub or hub is generating the test packet?

Looking at the schematic, you don't need TUSB212 U12 and UB4. You just need UB10 and UB3, but they have to be placed near the connector.

With UB10 and UB3 mounted, would you please capture the eye diagram when host is connected to PA and when host is connected to PB?

Thanks
David

0 vetrivel prakasam over 6 years ago in reply to David (ASIC) Liu

Prodigy 90 points

David,

I have mounted UB3 and UB10.

HUB is generating the test packet.

Please find the test results and suggest redriver settings.

Eyediagram vs redriver settings .xlsx

Why increase DC boost of 60mV or 80mV with AC boost level3 makes no enumeration? Always DC boost of 40mV makes enumeration perfect by eye fail.

Regards

P.Vetrivel

0 David (ASIC) Liu over 6 years ago in reply to vetrivel prakasam

TI__Guru**** 179776 points

Prakasam

When you change TUSB212 AC or DC boost setting, did you reset or power on TUSB212?

This is the procedure for device side eye diagram measurement.
1. Configure the TUSB212 to the desired AC and DC boost settings.
2. Power on (or toggle the RSTN pin if already powered on) the TUSB212
3. Connect a USB host, the USB-IF device-side test fixture, and USB device to the TUSB212. Ensure that the
USB-IF device test fixture is configured to the ‘INIT’ position
4. Allow the host to enumerate the device
5. Enable the device to transmit USB TEST_PACKET
6. Using SMA cables, connect the oscilloscope to the USB-IF device-side test fixture and ensure that the
device-side test fixture is configured to the ‘TEST’ position.
7. Execute the oscilloscope USB compliance software.
8. Repeat the above steps in order to re-test TUSB212 with different AC and DC boost settings.

Thanks
David

0 vetrivel prakasam over 6 years ago in reply to David (ASIC) Liu

Prodigy 90 points

David,

I did exactly the same procedure but it didn't help in Eye.

I want to know why 60mV/80mV DC boost settings make "No enumeration" ?

What will be minimum rest pulse width ( ON and OFF)?

If i don;t want to toggle the reset , simply Power on the re-driver will take AC/DC settings or Not? Please share the waveform for VCC & reset.

Regards

P. Vetrivel

0 David (ASIC) Liu over 6 years ago in reply to vetrivel prakasam

TI__Guru**** 179776 points

Prakasam

High DC boost could cause high speed false disconnect condition, which would cause enumeration to fail.

Please refer to Figure 1 of the TUSB212 datasheet, min reset pulse width is 20uS.

You can also power cycle the TUSB212 after changing the AC/DC setting and it will also load the AC/DC setting.

Thanks
David

0 vetrivel prakasam over 6 years ago in reply to David (ASIC) Liu

Prodigy 90 points

David,

I need a local onsite support to india cypress to debug this issue.

Please assign this case to TI bangalore FAE so that he can visit to cypress.

Cypress is located next to TI building in bangalore. Please expedite this .

Query:

Do we need a create the pulse for reset ?

Regards.

P.Vetrivel

0 David (ASIC) Liu over 6 years ago in reply to vetrivel prakasam

TI__Guru**** 179776 points

Prakasam

RSTN is an active low signal. If you are driving RSTN from high to low to reset TUSB212, then you need to drive RSTN high again to take TUSB212 out of reset.

Thanks
David

Interface

Interface forum

TUSB212: HS Signal quality fail - Eye shows rise time issue.