USB PD in STM32

[Nicolas P.]

Hello @Sankar_Eswaran 

What do you mean by "to change the power source" ?

Is the STM32L5 source or sink ?

If you are updating the source capabilities of the charger, you need to send the new capabilities to refresh the sink information.

Which API do you use ? Can you share your .cpd trace (see tools here) to understand the issue ?

You normally don't have to unplug the cable. That is the goal of the power delivery protocol : do live exchanges.

Regards,

Nicolas

[Sankar_Eswaran]

..

[LLECH.1]

Hello Sankar,

You can use USBPD_DPM_RequestSourceCapability() API in order the source to send its capabilities again.

Then you will be able to negociate a new contract with sink device.

Best Regards,

Lucas

[Sankar_Eswaran]

..

[LLECH.1]

Hello again Sankar,

I am not sure to understand if your device act as a source or as a sink ?

In case it is a source device you should call USBPD_DPM_RequestSourceCapability() API so that source sends its new source capabilities. 

In case it is a sink device you can request for source capabilities of source by using USBPD_DPM_RequestGetSourceCapability() API. It will enforce source to resend source capabilities.

In any case it would be easier to help you with a trace of the communication.

Best Regards,

Lucas