[Enhancement] Add date retention functionality for STM32F1xx based boards

src/rtc.c

@@ -33,7 +33,6 @@
  *
  ******************************************************************************
  */
-
 #include "rtc.h"
 
 #if defined(STM32_CORE_VERSION) && (STM32_CORE_VERSION > 0x01090000) &&\
@@ -346,17 +345,41 @@ void RTC_init(hourFormat_t format, sourceClock_t source, bool reset)
  RtcHandle.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
 #endif /* STM32F1xx */
 
+ /* Ensure backup domain is enabled before we init the RTC so we can use the backup registers for date retention on stm32f1xx baords */
+ enableBackupDomain();
+
  HAL_RTC_Init(&RtcHandle);
 
+#if defined(STM32F1xx)
+ // Copy date data back out of the BackUp registers
+ RTC_DateTypeDef BackupDate;
+ RTC_TimeTypeDef DummyTime;
+ uint32_t dateMem;
+ dateMem = HAL_RTCEx_BKUPRead(&RtcHandle, RTC_BKP_DR3);
+ dateMem |= HAL_RTCEx_BKUPRead(&RtcHandle, RTC_BKP_DR2) << 16;
+ memcpy(&BackupDate, &dateMem, sizeof(uint32_t));
+ if (IS_RTC_YEAR(BackupDate.Year) && IS_RTC_MONTH(BackupDate.Month) && IS_RTC_DATE(BackupDate.Date)) {
+ /* Change the date retrieved from the backup registers */
+ RtcHandle.DateToUpdate.Year = BackupDate.Year;
+ RtcHandle.DateToUpdate.Month = BackupDate.Month;
+ RtcHandle.DateToUpdate.Date = BackupDate.Date;
+ /* Read the time so that the date is rolled over if required */
+ HAL_RTC_GetTime(&RtcHandle, &DummyTime, RTC_FORMAT_BIN);
+ /* Store the date or it will revert again if we lose power before manually updating. */
+ if (BackupDate.Date != RtcHandle.DateToUpdate.Date) {
+ RTC_StoreDate();
+ }
+ }
+#endif
+
 #if !defined(STM32F1xx) && !defined(STM32F2xx) && !defined(STM32L1xx) || defined(STM32L1_ULPH)
  /* Enable Direct Read of the calendar registers (not through Shadow) */
  HAL_RTCEx_EnableBypassShadow(&RtcHandle);
 #endif /* !STM32F1xx && !STM32F2xx */
 
  HAL_NVIC_SetPriority(RTC_Alarm_IRQn, RTC_IRQ_PRIO, RTC_IRQ_SUBPRIO);
  HAL_NVIC_EnableIRQ(RTC_Alarm_IRQn);
- /* Ensure backup domain is enabled */
- enableBackupDomain();
+
 }
 
 /**
@@ -438,6 +461,12 @@ void RTC_GetTime(uint8_t *hours, uint8_t *minutes, uint8_t *seconds, uint32_t *s
  RTC_TimeTypeDef RTC_TimeStruct;
 
  if ((hours != NULL) && (minutes != NULL) && (seconds != NULL)) {
+#if defined(STM32F1xx)
+ /* Store the date prior to checking the time, this may roll over to the next day as part of the time check,
+ we need to the new date details in the backuip registers if it changes */
+ uint8_t current_date = RtcHandle.DateToUpdate.Date;
+#endif
+
  HAL_RTC_GetTime(&RtcHandle, &RTC_TimeStruct, RTC_FORMAT_BIN);
  *hours = RTC_TimeStruct.Hours;
  *minutes = RTC_TimeStruct.Minutes;
@@ -461,6 +490,13 @@ void RTC_GetTime(uint8_t *hours, uint8_t *minutes, uint8_t *seconds, uint32_t *s
  UNUSED(period);
  UNUSED(subSeconds);
 #endif /* !STM32F1xx */
+
+#if defined(STM32F1xx)
+ if (current_date != RtcHandle.DateToUpdate.Date) {
+ RTC_StoreDate();
+ }
+#endif
+
  }
 }
 
@@ -483,6 +519,9 @@ void RTC_SetDate(uint8_t year, uint8_t month, uint8_t day, uint8_t wday)
  RTC_DateStruct.WeekDay = wday;
  HAL_RTC_SetDate(&RtcHandle, &RTC_DateStruct, RTC_FORMAT_BIN);
  setBackupRegister(RTC_BKP_INDEX, RTC_BKP_VALUE);
+#if defined(STM32F1xx)
+ RTC_StoreDate();
+#endif
  }
 }
 
@@ -711,6 +750,17 @@ void RTC_Alarm_IRQHandler(void)
  HAL_RTC_AlarmIRQHandler(&RtcHandle);
 }
 
+#if defined(STM32F1xx)
+void RTC_StoreDate(void)
+{
+ /* Store the date in the backup registers */
+ uint32_t dateToStore;
+ memcpy(&dateToStore, &RtcHandle.DateToUpdate, 4);
+ HAL_RTCEx_BKUPWrite(&RtcHandle, RTC_BKP_DR2, dateToStore >> 16);
+ HAL_RTCEx_BKUPWrite(&RtcHandle, RTC_BKP_DR3, dateToStore & 0xffff);
+}
+#endif
+
 #ifdef __cplusplus
 }
 #endif

src/rtc.h

@@ -165,6 +165,10 @@ void RTC_GetAlarm(uint8_t *day, uint8_t *hours, uint8_t *minutes, uint8_t *secon
 void attachAlarmCallback(voidCallbackPtr func, void *data);
 void detachAlarmCallback(void);
 
+#if defined(STM32F1xx)
+void RTC_StoreDate(void);
+#endif
+
 #ifdef __cplusplus
 }
 #endif