Posted on January 05, 2018 at 18:02It is not working, so you'll need to keep your mind open. I would suggest checking to see if you can actually see the oscillator working, or if it just takes too long for LSERDY to signal. Check the low power domain is enabled. Check the signal by routing LSE to MCO (Pin PA8)
Dig harder for examples
STM32Cube_FW_L4_V1.10.0\Projects\STM32L432KC-Nucleo\Examples\RTC\RTC_Alarm\Src\stm32l4xx_hal_msp.c
/**
* @brief RTC MSP Initialization
* This function configures the hardware resources used in this example
* @param hrtc: RTC handle pointer
*
* @note Care must be taken when HAL_RCCEx_PeriphCLKConfig() is used to select
* the RTC clock source; in this case the Backup domain will be reset in
* order to modify the RTC Clock source, as consequence RTC registers (including
* the backup registers) and RCC_BDCR register are set to their reset values.
*
* @retval None
*/
void HAL_RTC_MspInit(RTC_HandleTypeDef *hrtc)
{
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
/*##-1- Enables the PWR Clock and Enables access to the backup domain ###################################*/
/* To change the source clock of the RTC feature (LSE, LSI), You have to:
- Enable the power clock using __HAL_RCC_PWR_CLK_ENABLE()
- Enable write access using HAL_PWR_EnableBkUpAccess() function before to
configure the RTC clock source (to be done once after reset).
- Reset the Back up Domain using __HAL_RCC_BACKUPRESET_FORCE() and
__HAL_RCC_BACKUPRESET_RELEASE().
- Configure the needed RTC clock source */
__HAL_RCC_PWR_CLK_ENABLE();
HAL_PWR_EnableBkUpAccess();
/*##-2- Configure LSE/LSI as RTC clock source ###############################*/
#ifdef RTC_CLOCK_SOURCE_LSE
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI | RCC_OSCILLATORTYPE_LSE;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
RCC_OscInitStruct.LSEState = RCC_LSE_ON;
RCC_OscInitStruct.LSIState = RCC_LSI_OFF;
if(HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC;
PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;
if(HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
#elif defined (RTC_CLOCK_SOURCE_LSI)
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI | RCC_OSCILLATORTYPE_LSE;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
RCC_OscInitStruct.LSIState = RCC_LSI_ON;
RCC_OscInitStruct.LSEState = RCC_LSE_OFF;
if(HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC;
PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSI;
if(HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
#else
#error Please select the RTC Clock source inside the main.h file
#endif /*RTC_CLOCK_SOURCE_LSE*/
/*##-2- Enable RTC peripheral Clocks #######################################*/
/* Enable RTC Clock */
__HAL_RCC_RTC_ENABLE();
/*##-4- Configure the NVIC for RTC Alarm ###################################*/
HAL_NVIC_SetPriority(RTC_Alarm_IRQn, 0x0F, 0);
HAL_NVIC_EnableIRQ(RTC_Alarm_IRQn);
}
