TPS65981: DisplayPort not being detected after HDP is asserted HIGH

Hi Rakesh,

Are there any available PD logs to look at?

Regards,

Raymond Lin

Hi Raymond,

Thanks for your response. We currently do not have a PD analyzer. Could you please suggest one?

Thanks

Hi Rakesh,

We recommend using the TotalPhase PD Analyzer as it's easy to use and provides very detailed information about the PD contracts between devices: https://www.totalphase.com/products/usb-power-delivery-analyzer/  Similar PD devices can help us debug. As of now, I can't say for certain what the issue is with the PDO contracts between the 981 and connected device. One thing I recommend is double check the Source/Sink Capabilities of the PD controller and make sure it matches the Device required specs. 

Please also do note that the TPS65981 is a NRND (Not Recommended for New Design) device as it only supports up to PD2.0, which is no longer certified by USBIF. 

Regards,

Raymond Lin

Hi Raymond,

    Thanks for the recommendation. We are arranging PD Analyzer for log, meanwhile please review our schematics so would not be any sch side dependency.

We are intending to use  device as DRP- Data. in alt mode 5V 3A.

Hi Rakesh,

Can you please fill out this spreadsheet and is there a pdf of the schematic available? This will help speed up the process. 

I will look into this and get back to you next week.

Thanks and Regards,

Raymond Lin

Fill out checklist: schematic_checklist_981_ONLY.xlsx

schematic_checklist_981_updated.xlsxAJLI_SMTS_TI.pdf

Hi Raymond,

         PFA PDF file of sch and updated excel sheet. 

Hi Rakesh,

I'll get back to you by Wednesday with the checklist.

Thanks and Regards,

Raymond Lin

Hi Raymond,

    Any Update?

Hi Rakesh,

Apologies for the delay, I am still currently working on reviewing your checklist. Internally checking with team about certain specifications. 

I will send back a reviewed checklist with comments tomorrow, thank you for your patience!

Best Regards,

Raymond Lin

ok. will wait.

Hi Rakesh,

Attached is the checklist, most of the specs are good there are some that I left comments on, please take a look to confirm. 

Thanks and Regards,

Raymond Lin

5618.schematic_checklist_981_updated.xlsx

Hi Raymond,

       I have updated the sheet and left comment on. please take a look.

5618.schematic_checklist_981_updated_1.xlsx

Hi Rakesh,

I will take a look and get back to you. 

Thanks and Regards,

Raymond Lin

Hi Raymond,

  Awaiting your response.

Hi Raymond, 

We have taken the PD communication data using the EZ PD module. Could you please go through the data? You will have to download this tool - https://softwaretools.infineon.com/tools/com.ifx.tb.tool.ezpdprotocolanalyzer in order to look at the decoded data. I have also attached an excel of the same data, however, that is not decoded. All of the above data is uploaded on google drive & the link to the folder is pasted below.

Looking forward to your reply.

Thanks.

PD data contents

Hi Rakesh,

I will take a look through the PD logs and get back to you as soon as possible!

Thanks and Regards,
Raymond Lin

Hi Raymond,

       Any update? 

Hi Rakesh,

Still working on your case, thank you for your patience!

Regards,

Raymond Lin

Hi Raymond,

Awaiting your response.

Hi Rakesh,

Can you re-elaborate what issue you're encountering?

From the PD logs, I can see a 5V/3A contract being negotiated as well as a Structured VDM of version 1.0. Is the PD controller supposed to provide power for the monitor or vice versa? Which end is supposed to be the Source and Sink?

Regards,

Raymond Lin

Hi Raymond,

           our issue is when device enters in alt mode there should be a screen blink but its is not happening and displays are not being power up. our device is smart glass having two displays, left and right eyes. our device is working as device sink. host might be laptop or mobile which support alt  mode. currently we are using laptop as host.

Are PD logs seems ok? if PD logs are ok then could it be a issue of AUX+ and AUX- or Super speed signals? 

Hi Rakesh, 

Are the displays on the smart glass one display device or are they two separate ones? 

Did you also configure in the Application Tool to the correct settings for your configuration? Picture below shows the register to configure display settings. 

Can you also check to see if this issue persists with a different cable? 

I'm also reaching out internally to get more insight about the PD logs. I will get back to you as soon as possible!

Thanks and Regards,
Raymond Lin

Hi Rakesh, 

Also forgot to ask in the previous post, is there some form of a ALT mode redriver/MUX in this system?

An example of a redriver is the TUSB546, which is often used in relation with our PD controllers: https://www.ti.com/product/TUSB546-DCI 

The block diagram below shows how it connects to the Type-C connector in conjunction with the PD, GPU, and USB host. 

Thanks and Regards,
Raymond Lin

Hi Raymond,

    Yes. We are using MUX(HD3SS460)have a look at the attached image

drive.google.com/.../view

Hi Raymond,

Please find the inline responses:

Are the displays on the smart glass one display device or are they two separate ones? 

- You can consider the displays on the smart glasses as a single one.

Did you also configure in the Application Tool to the correct settings for your configuration? Picture below shows the register to configure display settings. 

- Will check & revert back to you as these settings were done by a 3rd party vendor for us & those settings work (we get display data correctly & laptop screen blinks) in our previous smart glass which had no type C connector. It had a B2B receptacle. In our current glasses, we have simply replaced the B2B receptacle with a TYPE C connector with all the other hardware & configurations remaining the same. You can check the schematic too for TYPE C connector wiring.

Can you also check to see if this issue persists with a different cable? 

- Yes, we tried with multiple cables. However, the blink still does not come on the laptop screen.

Hi Rakesh,

Thank you for the update, I'll continue to look into this with your provided information and give you an update as soon as possible!

Thanks and Regards,

Raymond Lin

Hi Raymond,

    Awaiting your response.

Hi Rakesh, 

Still looking into this, I will send an update latest by the end of the week. 

Thanks and Regards,

Raymond Lin

Hi Raymond,

    Any updates?