Would really appreciate some help! This is giving me a right headache!! I am trying to write a value to one of the backup registers in the stm32f091 nucleo. Code functions but I don't get my number read back - it is always 0. Would REALLY appreciate help! uint32_t rtc_read_backup_reg(uint32_t BackupRegister) { RTC_HandleTypeDef RtcHandle; RtcHandle.Instance = RTC; Return HAL_RTCEx_BKUPRead(&RtcHandle, BackupRegister); } //++++++++++++++++ void rtc_write_backup_reg(uint32_t BackupRegister, uint32_t data) { RTC_HandleTypeDef RtcHandle RtcHandle.Instance = RTC; HAL_PWR_EnableBkUpAccess(); HAL_RTCEx_BKUPWrite(&RtcHandle, BackupRegister, data); HAL_PWR_DisableBkUpAccess(); } rtc_write_backup_reg(RTC_BKP_DR0,123); reg1 = rtc_read_backup_reg(RTC_BKP_DR0);

__PWR_CLK_ENABLE();   // normally in SystemClock_Config()
HAL_PWR_EnableBkUpAccess();

Perhaps, missing : <<code title=>> __PWR_CLK_ENABLE(); // normally in SystemClock_Config() HAL_PWR_EnableBkUpAccess(); <</code>>