TPS65987D: source capability time out

Patrick Chen(TPE System & Application)

Part Number: TPS65987D

Hi Sir,

My customer is using TPS65987D as a power source and found that TPS65987D will keep sending the source capability message for 9 seconds and stops if there is no response on sink side. I know this behavior is compliant with PD spec, but due to customer's sink device will need 18 second to boot and response to the PD command, so it will handshake failed.

And on the other hand, it will work fine with another PD adaptor, because this PD adaptor keep sending the source capability messages.

I saw the PD spec have a statement on section 6.6.6, "For a non-responsive device, the Policy Engine in a Source May either decide to continue sending Source_Capabilities Messages or to go to non-USB Power Delivery operation and cease sending Source_Capabilities Messages."

So I would like to ask your help to change our PD FW behavior and make it keep sending the source capability for a non-responsive device, I believe this will help to make TPS65987D more compatible.

Or if you could add this on configuration tool, that will also helps. Due to customer could not keep verify their platform without PD, we need your quick response to help us secure this socket.

Many thanks,

Patrick

over 6 years ago

0 Rahul Sharma16 over 6 years ago

TI__Expert 6430 points

Hi Patrick,

As per the USB-PD specification, the device must go to legacy mode after 15 seconds if it doesnt get any response from other end. Therefore it won't be possible to meet the customer's requirement.

Thanks,
Rahul

0 Patrick Chen(TPE System & Application) over 6 years ago in reply to Rahul Sharma16

TI__Expert 3430 points

Hi Rahul,

Thanks for help.

May I learn from you which chapter have this description?

I might need it to discuss with customer.

Patrick

0 Rahul Sharma16 over 6 years ago in reply to Patrick Chen(TPE System & Application)

TI__Expert 6430 points

Hi Patrick,

We enable CapsCounter in our architecture and if enabled we need to follow the below rule. Which asks us to stop sending source capabilities and go to legacy mode.

Thanks,

Rahul

0 Patrick Chen(TPE System & Application) over 6 years ago in reply to Rahul Sharma16

TI__Expert 3430 points

Hi Rahul,

On the spec, the CapsCounter is an optional, So if we did not implement the CapsCounter, we should be able to keep sending source capability.
Therefore it is possible to keeping sending source capability for more than 15 second without violate the spec, right?

We are hoping to keep our TPS65987D on this 5G application design and extend this project to other project with TPS65987D and what we need your help is provide a option on the GUI to keep sending the source capability. Also, I believe this should help TPS65987D to be more compatible.

Could you advise if you could help on this feature?

Thanks.
Patrick

0 Rahul Sharma16 over 6 years ago in reply to Patrick Chen(TPE System & Application)

TI__Expert 6430 points

Hi Patrick,

I'll check this and get back to you.

Thanks,
Rahul

0 Patrick Chen(TPE System & Application) over 6 years ago in reply to Rahul Sharma16

TI__Expert 3430 points

Hi Rahul,

Since we already post this on Jira, I will set this as resolve.

Thanks for your help and explain detail PD spec to me, it helpful and I learn a lot.

Thanks,

Patrick

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TPS65987D: source capability time out