TPS65988：Only Source

Hello, 

Please reconfigure register 0x28 Port Configuration to a DFP instead of DRP in both Port 1 and Port 2.

Thanks,

Emma

Dear Emma. Thank you for your reply

But my problem has not been solved yet. My product is connected to the laptop, and the laptop will still send PDO to my product.

Here's the PD log I recorded

Please help to analyze, thank you.

Dear Emma. Thank you for your reply

But my problem has not been solved yet. My product is connected to the laptop, and the laptop will still send PDO to my product.

Here's the PD log I recorded

Hello,

I can't quite make it out from the logs, but it looks like the laptop is sending get source caps with no response from your DFP device. Are you still seeing sinking from your DFP?

Thanks,

Emma

Hi Emma

The laptop will still charge my product, there is still voltage on VBUS, but the voltage will go from 0 to 5v and then from 5 to 0V and over and over again .

Thanks,

Hello,

Can you please post your project that you are using? I will evaluate this on an EVM. 

Thanks,

Emma

CSB_DOCK_V8_TRY_DRP_external_path_20V2_5A_DiscIden_Dell_VID_DFP.pjt

Hi Emma

This is the PJT file I changed (DRP changed to DFP)

thanks.

Hello,

I tested your configuration settings on my EVM. I was not able to reproduce the issue you saw. Can you check the debug register: Status and take a screen capture of the register? 

Also, please try this project and let me know the results: CSB_DOCK_V8_TRY_DRP_external_path_20V2_5A_DiscIden_Dell_VID_DFP_Edited.pjt

I edited the Port Control register to not process and power or data role swaps and got rid of all of the sink capability PDOs. 

Thanks,

Emma

Hi Emma

I don't know how to use the Debug Mode of TPS65981_2_6_7_8 Application Customization 6.1.1, how do I need to operate it?

After downloading the code generated by the PJT file you provided, the result is the same.

The notebook still reports source_cap, and then the product will not reply.

thanks.

Hi Emma

The expected behavior I want is that when the product is not connected to the power supply, there will be no PD communication between the two parties, and there will be no voltage on VBUS.

I read the value of 0x1A (Status Register).

If the product is powered, the value is 000000010020002d.

result：This product powers the laptop

If the power is not connected, sometimes the value is 0000000000000000, sometimes it is 0000000000000020.

result: The laptop keeps sending source_cap to the product, and there is voltage on VBUS (0V->5v->0V)

expected：The laptop will not send scource_cap to the product, and there is no voltage on VBUS.

thanks.

Hello,

Can you please send me a scope capture of the variation on VBUS? The current project you have loaded onto your board should not be negotiating anything.

Thanks,

Emma

Hi Emma

This is the variation range of VBUS voltage and current

The voltage range is approximately (5.07V to 0.2V)

This is the voltage change of CC1 and CC2

log.rar

This is the recorded PD LOG

Thanks.

Hello,

I am not sure why CC is toggling after you have made connection. Are you able to see this behavior on an EVM? 

Thanks,

Emma

Hi Emma

Sorry, no reply for a long time。

I don't have 65988 EVM,

and I want to know if TPS65988 can realize the situation that VBUS has no voltage.

thanks.

Hello,

I think that the TPS65988 should not negotiate a contract in this situation. As I was unable to reproduce this issue on the EVM using your project, I think you may have a hardware bug or are not able to load the project onto your device. How are you loading the project onto your device?

Thanks,

Emma

Hi Emma

Below is the schematic diagram of TPS65988

The download is a DFU device using STM32    

Our product is DOCK.

thanks

Hello,

The schematic did not attach. Can you clarify what "STM32" means in this case? 

Thanks,

Emma

Hi Emma,

TPS65988

TPS55288

The stm32f072 chip of st is used as MCU, and the external Flash of TPS65988 is updated through this chip.

thanks,

Hello,

I am looking into this issue and will try to replicate on my EVM. I will follow up with you next week.

Thanks,

Emma