STM32WB55RG issue with the USB VCP during CPU2 operation

[Mahendra Sondagar]

Hi...Community

Hope you all are doing well

Recently, I'm dealing with the STM32WB custom hardware

In my application, i need the USB VCP logs during the BLE operation

And that's how I'm using USB CDC for the communication with the serial terminal

For me, I'm getting the debug logs at the serial terminal until the code reaches to CPU2 boot

When CPU2 comes in to the picture then, suddenly CDC logs stops due to wireless stack initialisation

After some googling, I got to know that the CPU2 uses the RNG, and that's how it's stopping the USB clock

Unfortunately Peripherals code settings not seems to be working for me as per the application note AN5289

I have attached code snippets for the Peripheral clock settings here

However, the same code generating the debug logs with the Nucleo board because of the lower version of the wireless stack on a top of it!

My custom board is running with the cube SDK version 1.11.1

void PeriphClock_Config(void) {
#if (CFG_USB_INTERFACE_ENABLE != 0)
	RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = { 0 };
	RCC_CRSInitTypeDef RCC_CRSInitStruct = { 0 };
 
	/**
	 * This prevents the CPU2 to disable the HSI48 oscillator when
	 * it does not use anymore the RNG IP
	 */
	LL_HSEM_1StepLock( HSEM, 5);
 
	LL_RCC_HSI48_Enable();
 
	while (!LL_RCC_HSI48_IsReady())
		;
 
	/* Select HSI48 as USB clock source */
	PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USB;
	PeriphClkInitStruct.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
	HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
 
	/*Configure the clock recovery system (CRS)***********/
 
	/* Enable CRS Clock */
	__HAL_RCC_CRS_CLK_ENABLE();
 
	/* Default Synchro Signal division factor (not divided) */
	RCC_CRSInitStruct.Prescaler = RCC_CRS_SYNC_DIV1;
 
	/* Set the SYNCSRC[1:0] bits according to CRS_Source value */
	RCC_CRSInitStruct.Source = RCC_CRS_SYNC_SOURCE_USB;
 
	/* HSI48 is synchronized with USB SOF at 1KHz rate */
	RCC_CRSInitStruct.ReloadValue = RCC_CRS_RELOADVALUE_DEFAULT;
	RCC_CRSInitStruct.ErrorLimitValue = RCC_CRS_ERRORLIMIT_DEFAULT;
 
	RCC_CRSInitStruct.Polarity = RCC_CRS_SYNC_POLARITY_RISING;
 
	/* Set the TRIM[5:0] to the default value*/
	RCC_CRSInitStruct.HSI48CalibrationValue = RCC_CRS_HSI48CALIBRATION_DEFAULT;
 
	/* Start automatic synchronization */
	HAL_RCCEx_CRSConfig(&RCC_CRSInitStruct);
#endif
 
	return;
}

All suggestions and recommendations welcome 🙂

Thanks

Mahendra

[Remy ISSALYS · Accepted solution]

Hello,

Can you check HSI48ON bit in RCC_CRRCR register ?

You can also look BLE_TransparentModeVCP project for P-NUCLEO-WB55 USB Dongle which allows to use BLE and USB simultaneously. To use USB, it requires a semaphore which you need to set yourself. See : Building wireless applications with STM32WB Series microcontrollers - Application note Chapter Shared peripherals (Figure 9. Algorithm to use USB on CPU1).

Best Regards

[Mahendra Sondagar]

Hi.. @Remy ISSALYS​ 

Thanks for your feedback

The issue has been resolved

Actually, I made some mistake at VCP drivers

Now it's working

Thanks