I am currently using a STM32G081b eval board with a STM32G474QE MCU I am using the demoucpd example code if i plug in display for my laptop it works over usb c but doesn't on mobiles device does anyone know why?

NApps.1 · ‎2021-09-17

Nicolas P. · ‎2021-09-23

Logs should be here for MacOS : ~/Library/STM32CubeMonitor-UCPD/Logs

NApps.1 · ‎2021-09-27

I believe I may have found my problem I am trying to run one usb c port to do power and display. Does your library only allow a usb c port to be ether power or display?

I found in your usbpd_def.h some externs do this relate to default values found in the library file if so how can I change this as if I remove the #define __USBPD_DPM_CORE_C it just gives me a load of errors?

Yohann M. · ‎2021-09-27

No you could configure both port to do power and display... After the limitation is on HW side.

Description of our application is described in USB Power Delivery overview - stm32mcu.

'usbpd_def.h' is the definition file for USB-PD stack library... There are no relations with the Display port configuration which is done in usbpd_vdm_user.c file.

Externs are defined in usbpd_dpm_conf.h file and have a link the user code (usbpd_dpm_core.c) and then __USBPD_DPM_CORE_C is defined in the file.

Yohann

NApps.1 · ‎2021-09-27

So I am currently have the mind set the device needs to be a DRP to do power and display. Can I just set it up to be a Source ie provide power to say laptop/tablet and also do the display side of things?

Yohann M. · ‎2021-09-27

yes it is possible... You can request a data role swap to switch your data role if needed (to be in Source + Device mode).

Please refer to Managing USB power delivery systems with STM32 microcontrollers - User manual §4.4.1.

A DPM function is available: USBPD_DPM_RequestDataRoleSwap.

NApps.1 · ‎2021-09-27

Where would be the best place to request the Data Role Swap? Would it be in USBPD_DPM_Notification same as power role swap recommended here.

Yohann M. · ‎2021-09-27

Right it is the same suggestion:

/**
  * @brief  Callback function called by PE to inform DPM about PE event.
  * @param  PortNum The current port number
  * @param  EventVal @ref USBPD_NotifyEventValue_TypeDef
  * @retval None
  */
void USBPD_DPM_Notification(uint8_t PortNum, USBPD_NotifyEventValue_TypeDef EventVal)
{
/* USER CODE BEGIN USBPD_DPM_Notification */
  switch(EventVal)
  {
  case USBPD_NOTIFY_STATE_SRC_READY:
    {
      /* Check that the current data role is not already in UFP (device) */
      if (USBPD_PORTDATAROLE_DFP == DPM_Params[PortNum].PE_DataRole)
      {  
         if (USBPD_DPM_RequestDataRoleSwap(PortNum) != USBPD_OK)
         {
            /* Stack is BUSY... Suggest to postpone the request in using a timer
                 to delay this request... Refer to DPM_TimerSRCExtendedCapa usage in 
                 EVAL Demonstration */
            DPM_START_TIMER(PortNum, DPM_TimerRetryDRS, 100);
      }
    }
    break;
  default :
    break;
  }
/* USER CODE END USBPD_DPM_Notification */
}

Usage timer in DPM can be found HERE...

Yohann

NApps.1 · ‎2021-09-28

Hi Yohann,

Thanks for that I have just tried it seems to work once I get charge and display on both laptop/display however it only works once if i unplug and plug back in i get charge but no display?

Yohann M. · ‎2021-09-28

Hi @NA.1067pps

UCPD log can help to understand the issue...

Yohann

NApps.1 · ‎2021-09-28

Here you go I had it display on tablet unplug plug back in and then get no display. If thats any help