TPS65988EVM: Not able to get the VDM in user alternet mode.

Niket Shah2

Part Number: TPS65988EVM
Other Parts Discussed in Thread: TPS65988

I have two TPS65988 boards connected with each other on a USB type C connecter. Both the devices are configured for alternate mode. Device A will send the VDM upon entering the alternate mode and Device B will receive it. My aim is to get that received VDM. I am referring SLVAE16A document for this POC. Device A will sink the power from Device B. I am using the EVK as a device B and my custom board as a Device A. I am using debug mode to check the received VDM. I checked register 0x61 for VDM but was not able to receive the VDM. I attached the configuration file for both the devices along with the screenshot of EVK. Please let me know why am not able to get the VDM on EVK? As you can see below the image I am not able to receive the sent VDO.

DeviceA_alternate mode.pjt DeviceB_alternate mode.pjt

over 4 years ago

0 Adam Mc Gaffin over 4 years ago

TI__Mastermind 30000 points

Hello Niket,

Do you have access to a PD analyzer such as a total phase? I would like to verify that the VDM messages are being sent

https://www.totalphase.com/products/usb-power-delivery-analyzer/

0 Niket Shah2 over 4 years ago in reply to Adam Mc Gaffin

Prodigy 210 points

Hi,

I do not have the PD analyzer. As per the configuration shown in the document(SLVAE16A) it should send the VDM. And if you observed the screenshot then it shows the VDO count(Number of valid VDOs). Initially, the count was zero before connecting the two devices.

0 Adam Mc Gaffin over 4 years ago in reply to Niket Shah2

TI__Mastermind 30000 points

Hi Niket,

I will look through this item and respond to you later this week

0 Niket Shah2 over 4 years ago in reply to Adam Mc Gaffin

Prodigy 210 points

Hi,

Any update on this?

0 Adam Mc Gaffin over 4 years ago in reply to Niket Shah2

TI__Mastermind 30000 points

Hi Niket,

I would recommend acquiring a PD analyzer to read the messages being sent between the two EVMs. This will help root cause the problem to determine if the messages are being sent in the first place. If we see the message in the PD logs, and they are not showing up on the receiving device, then we know that is where the issue lies. If we are not seeing the messages in the PD logs, then we know the issue is due to the device sending the VDM

0 Niket Shah2 over 4 years ago in reply to Adam Mc Gaffin

Prodigy 210 points

Untitled Folder.zip

Hi,

Please find the attached logs.

0 Hari Patel1 over 4 years ago in reply to Niket Shah2

TI__Genius 12700 points

Hi Niket,

I will take a look into these and provide additional feedback later this week.

Thank you,

Hari

0 Niket Shah2 over 4 years ago in reply to Hari Patel1

Prodigy 210 points

Okay. I have attached configuration files in the above converstaions if you need them.

0 Hari Patel1 over 4 years ago in reply to Niket Shah2

TI__Genius 12700 points

Hi Niket,

Yes I will look into those as well. From the PD logs though, it looks like the PD controller went to Enter Mode and you can see the data for those messages.

Thank you,

Hari

0 Niket Shah2 over 4 years ago in reply to Hari Patel1

Prodigy 210 points

Hi Hari,

InEnter Mode command VDO objects are missing. As per the document SLVAE16A, after sending the Enter mode command VDO objects should come. We sent 0x1122334455667788 in VDO object. This data is not visible in the logs.

0 Hari Patel1 over 4 years ago in reply to Niket Shah2

TI__Genius 12700 points

Hi Niket,

Alright, yes it doesn't look like that shows up. I'll need some more time to look into this issue.

Thank you,

Hari

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TPS65988EVM: Not able to get the VDM in user alternet mode.