TPS65986EVM: Interfacing TPS65986EVM & DP-EXPANSION-EVM with an LG G5 cellphone

Roy Hsu

Part Number: TPS65986EVM
Other Parts Discussed in Thread: DP-EXPANSION-EVM, HD3SS460

Hi,

I am an FAE from Taiwan and am facing an issue with TPS65986EVM & DP-EXPANSION-EVM .

My customer wants to transfer the cellphone screen to an external HDMI monitor. There's a mini-DP to HDMI dongle interfaced between the DP-EXPANSION Board and the monitor.

From the PD log obtained from an Lecroy Protocol Analyzer, everything seemed fine and I could see that the device had already entered Alternate Mode with HPD State equaled to HIGH.

However, we could never see the display on the HDMI monitor. I have the PD trace file attached here.

For your reference, we are sure that the LG cellphone works fine and we also tested with a mini-DP to VGA dongle but it also didn't work.

Please let me know what I can do next to figure out the problem. Thank you!

986 log.usb

Best regards,

Roy Hsu

over 8 years ago

0 Eric Beljaars over 8 years ago

TI__Mastermind 36756 points

Hi Roy,

Thank you for including the PD logs. Can you confirm a few things for me:

1. Does D1_BA (HPD LED) on the DisplayPort Sink Board turn on when you attach the phone?

2. What is the configuration that is on your TPS65986-EVM? Is it configured to be a UFP_D for DisplayPort mode?

Thank you,
Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

Thanks for the reply!

1. Yes. The HPD LED was ON. However, it didn't light up when I attached the phone but the monitor.

2. Please see the picture below. Also, I have the project file, the low-region and the full-flash bin files sent to you in a separate email since the format is nor supported here.

Best regards,

Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

Do you have a Type-C to DisplayPort cable to test the video output from the LG G5?

Thank you,
Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

No, I don't. We actually tested the LG G5 with a Type-C to HDMI dongle (which uses a Realtek controller).

We were able to see the display on the monitor with that cable.

Other than that, we also used a laptop as the source but weren't able to see the display with our evms.

This same laptop worked with that Type-C to HDMI dongle, too!

Best regards,

Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

I was able to reproduce the issue on my end using a macbook as the display source. There is an issue in the configuration for the UFP template. I noticed that GPIO 0 and GPIO 3 are swapped. You should set GPIO 0 to "Either DP or USB Event" and set GPIO 3 to "AMSEL Event" after changing this, the issue was resolved on my end.

Thank you,
Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

That's a very good input. I guess those GPIOs are controlling the HD3SS460 on the DP-EXPANSION board, right?

I'll try that tomorrow and let you know about the result!

Thank you!

Best regards,
Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

Correct, those GPIOs control the HD3SS460 MUX on the DP-Expansion board.

Thank you,
Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

I wasn't able to solve the problem after making those changes.

When I had everything connected, I found that AUX_P was high (about 2.9V) and AUX_N was low.

Do you think that this has to do with the issue? If not, what else could be the problem?

Thank you!

Best regards,

Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

Can you check to see if the following resistors are DNP on your DP-Expansion EVM?
R2
R3
R4
R5
R7
R8
R9
R10

These should all be removed from the DP-Expansion EVM for it to function properly.

Thank you,
Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

I've checked that all eight resistors are removed from the DP-Expansion EVM.

What's the purpose for the eight resistors?

What information do you need from me to figure out the cause?

Thank you!

Best regards,

Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

R2, R3, R4, & R5 are pull-up/down options on the Aux_P and Aux_N lines. R7, R8, R9, & R10 allow you to adjust the CFG1 and CFG2 pins on the DP connector. All 4 of these should be DNP.
With the configuration change I suggested in my previous post I am able to get the TPS65986 with DP Expansion board working with a Samsung S8+ phone and multiple Type-C laptops.

Thank you,
Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

I appreciate your inputs so far!

However, with the configuration you suggested, I still couldn't get this issue fixed.

Is there any other thing that I can check? What are the procedures that you'd take for this kind of problem?

Since this issue has been going on for a while, I'd probably need to schedule a call with you to go over this!

Does that sound workable for you?

Thank you!

Best regards,

Roy Hsu

0 Roy Hsu over 8 years ago in reply to Roy Hsu

TI__Genius 9400 points

Hi Eric,

To be sure that I didn't do anything wrong with the settings, could you please provide me with the project file that you used?

Thank you!

Best regards,

Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

I have attached my project file. I have tested this one with multiple Type-C laptops and a Samsung S8+ Type-C phone. All cases are working well.

986 UFP DP.pjt

Thank you,

Eric

0 Roy Hsu over 8 years ago in reply to Eric Beljaars

TI__Genius 9400 points

Hi Eric,

Thanks for sharing the project file!

I tested with a Samsung S8 today but still couldn't get the EVM work with the project file you provided.

Below are some actions that I'd need your help with:

1. Could you please help me to test the attached bin files with your EVM? The difference between my bin files and yours is that I set the max sink current to 0.9A since LG G5 only supports up to 0.9A.

2. I measured the AUX_P and AUX_N waveforms but they didn't seem correct. Could you please take a look at the waveforms attached?

My understanding is that the waveforms should look like square waves, by which that means that the source and sink device are talking to each other.

Besides, the results I got with an HDMI monitor and a VGA monitor were different. ( Gray: AUX_N, Blue, AUX_P)

Could you please let me know what could be the problems?

Upper:HDMI Monitor Lower: VGA monitor

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/138/986-UFP-DP-bin-files.7z

Thanks a lot for the support!

Best regards,

Roy Hsu

0 Eric Beljaars over 8 years ago in reply to Roy Hsu

TI__Mastermind 36756 points

Hi Roy,

I used your full flash image on my EVM and it is working and able to display on the monitor.
For your AUX_P & AUX_N scope shots, at what point did you take a capture? Was this recorded after the monitor was plugged in or was this during the display port alternate mode negotiation?

Thank you,
Eric

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TPS65986EVM: Interfacing TPS65986EVM & DP-EXPANSION-EVM with an LG G5 cellphone