PCD Connect and Disconnect callbacks are not called anywhere in the code

[fronders]

Describe the set-up

• CubeMX v6.4.0 with CubeWB v1.13.1

Describe the bug
Generated code in usbd_conf.c contains HAL_PCD_ConnectCallback() and HAL_PCD_DisconnectCallback():

/**
  * @brief  ConnectCallback callback.
  * @param  hpcd: PCD handle
  * @retval None
  */
void HAL_PCD_ConnectCallback(PCD_HandleTypeDef * hpcd)
{
  USBD_LL_DevConnected(hpcd->pData);
}

/**
  * @brief  Disconnect callback.
  * @param  hpcd: PCD handle
  * @retval None
  */
void HAL_PCD_DisconnectCallback(PCD_HandleTypeDef * hpcd)
{
  USBD_LL_DevDisconnected(hpcd->pData);
}

But these callbacks are not called anywhere in stm32wbxx_hal_pcd. This is same independent of selected USB Device Class. However other callbacks like HAL_PCD_ResumeCallback() are called and executed. Is this a bug, or what if the point of these functions then?

[ALABSTM]

Hi @fronders,

Would you mind double-checking this point please? Below code snippets show that both callbacks are defined in stm32wbxx_hal_pcd.c since version 1.13.0 of the STM32CubeWB firmware.

With regards,

STM32CubeWB/Drivers/STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_pcd.c

Lines 148 to 149 in 398d0fb

	hpcd->ConnectCallback = HAL_PCD_ConnectCallback;
	hpcd->DisconnectCallback = HAL_PCD_DisconnectCallback;

STM32CubeWB/Drivers/STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_pcd.c

Lines 1295 to 1303 in 398d0fb

	__weak void HAL_PCD_ConnectCallback(PCD_HandleTypeDef *hpcd)
	{
	/* Prevent unused argument(s) compilation warning */
	UNUSED(hpcd);
	/* NOTE : This function should not be modified, when the callback is needed,
	the HAL_PCD_ConnectCallback could be implemented in the user file
	*/
	}

STM32CubeWB/Drivers/STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_pcd.c

Lines 1310 to 1318 in 398d0fb

	__weak void HAL_PCD_DisconnectCallback(PCD_HandleTypeDef *hpcd)
	{
	/* Prevent unused argument(s) compilation warning */
	UNUSED(hpcd);
	/* NOTE : This function should not be modified, when the callback is needed,
	the HAL_PCD_DisconnectCallback could be implemented in the user file
	*/
	}

[fronders]

Hello @ALABSTM!

Yes, these functions are assigned to ConnectCallback and DisconnectCallback pointer of hpcd. The problem is that neither the functions HAL_PCD_ConnectCallback() & HAL_PCD_DisconnectCallback() themselves, nor those function pointers you mentioned never get called anywhere from code.

In contrast HAL_PCD_ResumeCallback() and hpcd->ResumeCallback does get executed in HAL_PCD_IRQHandler() as seen below:

STM32CubeWB/Drivers/STM32WBxx_HAL_Driver/Src/stm32wbxx_hal_pcd.c

Lines 1065 to 1069 in 398d0fb

	#if (USE_HAL_PCD_REGISTER_CALLBACKS == 1U)
	hpcd->ResumeCallback(hpcd);
	#else
	HAL_PCD_ResumeCallback(hpcd);
	#endif /* USE_HAL_PCD_REGISTER_CALLBACKS */

So my question is still the same - what is the point of these functions then?

Regards

[ALABSTM]

Hi @fronders,

Actually, both callbacks you pointed out are redefined at application level, as you can see from the code snippet below.

The fact is that, in the case of the STM32WB microcontrollers, the USB peripheral does not support the V-Bus sensing. This requires rather using ADC or GPIO. In both cases, these callbacks could, for instance, be called by the corresponding ADCx_IRQHandler() or EXTIx_IRQHandler() that should be defined in the stm32wbxx_it.c file.

I hope this answers your question.

With regards,

STM32CubeWB/Projects/P-NUCLEO-WB55.Nucleo/Applications/USB_Device/CDC_Standalone/USB_Device/Target/usbd_conf.c

Lines 355 to 388 in 398d0fb

	#if (USE_HAL_PCD_REGISTER_CALLBACKS == 1U)
	static void PCD_ConnectCallback(PCD_HandleTypeDef *hpcd)
	#else
	void HAL_PCD_ConnectCallback(PCD_HandleTypeDef *hpcd)
	#endif /* USE_HAL_PCD_REGISTER_CALLBACKS */
	{
	/* USER CODE BEGIN HAL_PCD_ConnectCallback_PreTreatment */
	/* USER CODE END HAL_PCD_ConnectCallback_PreTreatment */
	USBD_LL_DevConnected((USBD_HandleTypeDef*)hpcd->pData);
	/* USER CODE BEGIN HAL_PCD_ConnectCallback_PostTreatment */
	/* USER CODE END HAL_PCD_ConnectCallback_PostTreatment */
	}
	/**
	* @brief Disconnect callback.
	* @param hpcd: PCD handle
	* @retval None
	*/
	#if (USE_HAL_PCD_REGISTER_CALLBACKS == 1U)
	static void PCD_DisconnectCallback(PCD_HandleTypeDef *hpcd)
	#else
	void HAL_PCD_DisconnectCallback(PCD_HandleTypeDef *hpcd)
	#endif /* USE_HAL_PCD_REGISTER_CALLBACKS */
	{
	/* USER CODE BEGIN HAL_PCD_DisconnectCallback_PreTreatment */
	/* USER CODE END HAL_PCD_DisconnectCallback_PreTreatment */
	USBD_LL_DevDisconnected((USBD_HandleTypeDef*)hpcd->pData);
	/* USER CODE BEGIN HAL_PCD_DisconnectCallback_PostTreatment */
	/* USER CODE END HAL_PCD_DisconnectCallback_PostTreatment */
	}

[fronders]

Yeah, I saw they are redefined at application level - that's exactly what my initial post mentions. But still these callbacks never get called anywhere.

The fact is that, in the case of the STM32WB microcontrollers, the USB peripheral does not support the V-Bus sensing. This requires rather using ADC or GPIO. In both cases, these callbacks could, for instance, be called by the corresponding ADCx_IRQHandler() or EXTIx_IRQHandler() that should be defined in the stm32wbxx_it.c file.

Thanks, that is what I was looking for. Would've been nice if it would have been mentioned somewhere in the sources.
Is there a point in generating the callbacks in the application code if they are never used? This is what gets users confused