HSE not enabled in SystemClock_Config code generated by STM32CubeMX

[BitBanger46]

Even though I configure the RCC to use an external high speed crystal as a clock source (HSE), the HSI remains selected even after the SystemClock_Config routine is executed!! (I have checked the HSE pins and it appears that the clock driver (PH0/PH1) is not turned on.)

The SystemClock_Config code generated is:

void SystemClock_Config(void)

{

  RCC_OscInitTypeDef RCC_OscInitStruct = {0};

  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};

  /** Configure LSE Drive Capability 

  */

  HAL_PWR_EnableBkUpAccess();

  /** Configure the main internal regulator output voltage 

  */

  __HAL_RCC_PWR_CLK_ENABLE();

  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE3);

  /** Initializes the CPU, AHB and APB busses clocks 

  */

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;

  RCC_OscInitStruct.HSEState = RCC_HSE_ON;

  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;

  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

  {

   Error_Handler();

  }

  /** Initializes the CPU, AHB and APB busses clocks 

  */

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSE;

  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)

  {

   Error_Handler();

  }

  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USART1|RCC_PERIPHCLK_USART2

               |RCC_PERIPHCLK_SDMMC1;

  PeriphClkInitStruct.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;

  PeriphClkInitStruct.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;

  PeriphClkInitStruct.Sdmmc1ClockSelection = RCC_SDMMC1CLKSOURCE_SYSCLK;

  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)

  {

   Error_Handler();

  }

}

The oscillator type is set to HSE and the oscillator state is set to HSE_ON.

I added the following code at the end of the routine:

   uint32_t lClkFreq=HAL_RCC_GetHCLKFreq ();

The value of lClkFreq is 16000000 (16 MHz) which is the frequency of the internal HSI.

I should mention that I did not check the Master Clock Output 1 box in the RCC Configuration and Mode dialog box.

I have attached an image of the RCC Configuration and Mode as well as the Clock Configuration diagram.

[TDK]

Your clock configuration is using HSI as a clock source. HSE might be enabled, but it's not being used as a clock source, at least in the picture you linked.

[BitBanger46]

The picture is incorrect! The correct picture is attached.

[TDK]

What's probably happening is one of these functions is failing, Error_Handler is being called, but because Error_Handler has no content, it returns as if nothing went wrong.

Consider adding "while (1);" within Error_Handler, or step through your code to find out what's failing.

[BitBanger46]

You are indeed correct!! I stepped through the code and found that the failure occurs in the HAL_RCC_ClockConfig routine when the following code is executed:

/* HSE is selected as System Clock Source */

  if(RCC_ClkInitStruct->SYSCLKSource == RCC_SYSCLKSOURCE_HSE)

  {

    /* Check the HSE ready flag */

    if(__HAL_RCC_GET_FLAG(RCC_FLAG_HSERDY) == RESET)

    {

     return HAL_ERROR;

    }

  }

The RCC_FLAG_HSERDY is clear indicating that the HSE oscillator is not running!

Any thoughts???

[TDK]

Is this a custom board? Is the HSE connected properly? Not real sure.

[Piranha]

And what does this code do?

[BitBanger46]

Yes, it is a custom board and I have verified that the external crystal is connected across PH0 and PH1 with 18 pF load capacitors on each lead.

[BitBanger46]

The code shown above is generated by the STM32CubeMX IDE in accordance with the RCC clock configuration shown in the second picture above. It is supposed to set the appropriate bits in the RCC register control the clock sources and speeds.

[Piranha]

Look carefully - there is a link in my post... Did you see it? The recent change of color for links in this forum is "great"!