TPS65982: VCONN_Swap condition

Yoshimura-san,

If I understand the question, the customer is looking for a way to send a VCONN_SWAP.

I see in their project file, they have the "Process VCONN Swap" checked which meant the PD device can accept VCONN Swap request already, but if they want to initiate the swap they can set the "Initiate VCONN Swap" in Control Config register (0x29) to initiate the swap.

The customer's GUI and FW version are of an older version, there is a newer version available now GUI 6.1.1 and FW 0001.12.09.

I  have attached a project file with this GUI version and has the "Initiate VCONN Swap" set.

Regards,

Peter

Hi, pdjuandi-san,

>If I understand the question, the customer is looking for a way to send a VCONN_SWAP.

>I see in their project file, they have the "Process VCONN Swap" checked which meant the PD device can accept VCONN Swap request already, but if they >want to initiate the swap they can set the "Initiate VCONN Swap" in Control Config register (0x29) to initiate the swap.

-> No.

We want to know all conditions which TPS65982 issue VCONN_Swap

in our project file.

>The customer's GUI and FW version are of an older version, there is a newer version available now GUI 6.1.1 and FW 0001.12.09.

-> We cannnot change PD FW, because our products has been already in MP.

Best Regards,

Peter,  I have escalation from customer today.  Would you please advise it ?  They need VCONN_Swap condtions.

In addition to this question, Customer found TPS65987DDH show different situation. please advice why reason about spec change?

Best Regards,

Hi,

Sorry for the late response as I do not get any e2e notification after my respond back in July 7th.

VCONN_SWAP is PD control Message either source or sink can initiate this message.

In TPS65982, if we are source the vconn swap happens only if the far-end device requested it.

If we are sink then vconn_swap request happens when we need to talk to the cable say after a data role swap.

On GUI/FW, understood.

I don't understand the statement here " Customer found TPS65987DDH show different situation. please advice why reason about spec change?" What situation and what is changed? Please provide more detail.

Regards,

Peter

Please kindly Share CONN_SWAP submittion condition based on email attached proj file (email date: July7, 2020)

Then this is 2nd question

TPS65982 specification:  DR_Swap condition -> DFP -> VCONN_SWAP

TPS65982DDH does not show this behavior,  

Could you please share why this specification change?

In your project file, you have the following setting for VCONN_SWAP:

1. In system Configuration (0x28), you have VCONN supported as DFP/UFP (accept VCONN_Swap requests): this allows VCONN_Swap irregardless you are DFP or UFP.

2. In Control Configuration (0x29), you have process VCONN SWAP and initiate VCONN SWAP checked so this ties to the above that you want to provide VCONN.

When a port connects as Source, it automatically becomes VCONN Owner.

When it connects as sink and wanted to become a DFP it issues a DR_SWAP and it needs to perform cable discovery, so in this case it needs to be a VCONN owner and issue a VCONN_SWAP.

What is TPS65988DH not showing?

Yoshimura-san, please work with the customer and understand the issue.

Regards,

Peter

Hi, Mr.Peter,

 I'm Takki.(Maurice's colleague)

Maybe you have wrong understanding of our request.
We want controller NOT to issue VCONN Swap automatically.

Please recognize that we did check only "Proccess Vconn Swap" in "0x29 control configuration" of both F/Ws of TPS65982 and TPS65988.(We didn't check "Initiate Vconn Swap")

But the behavior of F/W has been changed between TPS65982<>TPS65988.

About TPS65982, if it is sink then Vconn_Swap_Request will be issued after a DR swap.
(As Mr. Peter said in the post of Jul 17, 2020 3:47 PM)
On the contrary, TPS65988 will not send Vconn Swap after DR swap although if it is sink.

TPS65982's behavior is not desirable for us.
So we want to understand why only TPS65982 issue Vconn Swap automatically in such situation.

And we want to know how to prevent the Automatic Vconn Swap via I2C after power on, without changing F/W binary.

Please tell us the way if it is possible.

Hi, Mr. Peter.

Please delete the pjt file on your post of Jul 7, 2020 2:52 PM

(TPS65982_v0001.12.09_v6.1.1_20200707.pjt)

It includes our information.

Takki

Takki-san,

Thank you for the explanation, it helps clarify the issue.

Is it possible to send both TPS65982 and TPS65988 project files and PD logs that show these differences to me?

You can send them through Yoshimura-san instead of posting them here.

Let me clarify on the VCONN_Swap between the TPS65982 and TPS65988.

On TPS65982, VCONN_Swap follows when DR_Swap occurs, but on TPS65988 VCONN_Swap occurs only if there's a need for new DFP to talk to the cable. 

What's the reason you don't want VCONN_Swap occurs automatically on TPS65982?

Regards,

Peter

Nakagawa-san,

Thanks for the pd log.

Vconn_swap should not cause VBUS to discharge, something in this system causes the behavior.

And as you mentioned this is only on some devices, maybe should look into the configuration or setup.

There's no I2C command to remove this vconn_swap step.

Regards,

Peter