TPS65988DJ: TD.1.1 Low Frequency Periodic Signaling TX Test

Jason Ciou

Expert 3600 points

Part Number: TPS65988DJ

Hi team,

My customer go to Allion to test the USB3 compliance test.

There is one fail item, TD.1.1 Low Frequency Periodic Signaling TX Test.

The problem is when type C flipped CC2 no superspeed.

The TPS65988DJ as sink mode.

Please see below waveform to get more detail.

The tester only have CC1, they don't have CC2.- which mean they want to test type C if could be flip or not.

Without flip type C CC1 connect to PD controller CC1. You could see the scope PD controller CC1 is high, CC2 is low, so the PD controller behavior is correct.

With flip type C CC1 should connect to PD controller CC2.You could see the scope PD controller CC1 is high, CC2 is low, so the PD controller behavior is wrong. the CC2 should be High not CC1.

Do you have any idea with that issue?

over 3 years ago

0 Ghouse Mohiuddin23 over 3 years ago

TI__Expert 8050 points

I would suggest to test this on EVM. If PD controller configuration is DFP, then both pins on receptacle side PD controller will be high when there is no connection. When connection is made say on cc2 then cc2 voltage will show lower connection voltage depending on current capability setting.

The tester will not see any voltage on cc2 as it will not be connected.

0 Jason Ciou over 3 years ago in reply to Ghouse Mohiuddin23

TI__Expert 3600 points

Hi Ghouse,

You mean I can use two EVM, one is DRP, the other is Sink. but we don't have only CC1 cable on hand.

if I need to duplicate I need to use only CC1 cable to do right?

but do you think the behavior is normal? when cable is connect to CC2, why CC1 still has voltage and why CC2 doesn't have any voltage.

I think the behavior is wrong.

Jason

0 Ghouse Mohiuddin23 over 3 years ago in reply to Jason Ciou

TI__Expert 8050 points

Cable always have only one CC pass through and other CC would be an Ra connection. That is why you see this. The CC1 maybe showing voltage because the cable doesn't have Ra but is unconnected state. The tester doesn't know anything about CC1 in this case.

You should focus on what error tester is throwing. I don't think CC1 voltage is a cause here. If tester is saying orientation issue then look at orientation event from PD controller is correctly controlling the USB Hub.

0 Jason Ciou over 3 years ago in reply to Ghouse Mohiuddin23

TI__Expert 3600 points

Hi Ghouse ,

My concern is when flip(second figure), I think CC1 should not have same voltage(PD controller as sink not DRP mode).

Because CC1 is connected to CC2 of PD controller, I think the voltage should be on the CC2 not CC1.

the fail reason is the tester cannot detect the CC2 when flip.

But when my customer using standard cable to test with/without flip function, both could work, you could see below figure,

Jason

0 Ghouse Mohiuddin23 over 3 years ago in reply to Jason Ciou

TI__Expert 8050 points

Jason, Look at this thread and it can help you understand this better.

(+) TPS65987D: CC lines status in DFP mode - Interface - INTERNAL forum - Interface - INTERNAL - TI E2E support forums

I think the cable on the tester may have an issue. Find out what tester and what setup this is. We have done several compliance test and we didn't have any such issue. Orientation detection is a basic thing. which is well tested. You can also refer to USB Type-C spec on usb.org.

0 Jason Ciou over 3 years ago in reply to Ghouse Mohiuddin23

TI__Expert 3600 points

Hi Ghouse,

Got it, thanks.

I will check it.

Jason

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TPS65988DJ: TD.1.1 Low Frequency Periodic Signaling TX Test