STM32CubeMX 4.22.1 STM32L476JGYx SystemClock_Config Bug

Posted on September 20, 2017 at 12:35

Hi guys.

I'm working in a STM32L476JGY based project using the board STEVAL-STLCS02V1.

The code generated by the Cube using the default clock configuration 'forgets' initialize the M value of the PLL struct, see original code:

/** System Clock Configuration

*/

void SystemClock_Config(void)

{

RCC_OscInitTypeDef RCC_OscInitStruct;

RCC_ClkInitTypeDef RCC_ClkInitStruct;

RCC_PeriphCLKInitTypeDef PeriphClkInit;

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

*/

RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;

RCC_OscInitStruct.MSIState = RCC_MSI_ON;

RCC_OscInitStruct.MSICalibrationValue = 0;

RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;

RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;

RCC_OscInitStruct.PLL.PLLN = 40;

RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV7;

RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;

RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;

if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

{

_Error_Handler(__FILE__, __LINE__);

}

...

it's very strange that the call to HAL_RCC_OscConfig returns with a HAL_OK, but later, when the function tries to configure the PPLSAI1 it fails and the system is blocked on the _Error_Handler loop.

I fixed the problem initializing the M value on the PLL adding the following line:

RCC_OscInitStruct.PLL.PLLM = 1; // STM32CubeMX forgets that line.

#steval-stlcs02v1 #stm32l476jgyx #systemclock_config #stm32cubemx-4.22.1