I work with stm32 F302, custom board. I need to implement the RTC function, with the connection of the battery. I ran into a problem, when the main power source is turned off, the battery can support the RTC clocking only for 10 minutes, after 10 minutes the RTC timer is reset. In the initialization function, I commented on the automatic setting of time and date (image 1). I use the built-in clock generator (LSI RC) as a clock source. I attach my initialization function , as well as a screenshot of clock configuration. I also attach the battery connection diagram to the Vbat
Vbat connection
Clock configuration
static void MX_RTC_Init(void)
{
/* USER CODE BEGIN RTC_Init 0 */
/* USER CODE END RTC_Init 0 */
// RTC_TimeTypeDef sTime = {0};
// RTC_DateTypeDef sDate = {0};
/* USER CODE BEGIN RTC_Init 1 */
/* USER CODE END RTC_Init 1 */
/** Initialize RTC Only
*/
hrtc.Instance = RTC;
hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
hrtc.Init.AsynchPrediv = 127;
hrtc.Init.SynchPrediv = 311;
hrtc.Init.OutPut = RTC_OUTPUT_DISABLE;
hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
hrtc.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
if (HAL_RTC_Init(&hrtc) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN Check_RTC_BKUP */
/* USER CODE END Check_RTC_BKUP */
/** Initialize RTC and set the Time and Date
*/
sTime.Hours = 0x16;
sTime.Minutes = 0x54;
sTime.Seconds = 0x0;
sTime.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
sTime.StoreOperation = RTC_STOREOPERATION_RESET;
// if (HAL_RTC_SetTime(&hrtc, &sTime, RTC_FORMAT_BCD) != HAL_OK)
// {
// Error_Handler();
//}
sDate.WeekDay = RTC_WEEKDAY_MONDAY;
sDate.Month = RTC_MONTH_JUNE;
sDate.Date = 0x26;
sDate.Year = 0x23;
// if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BCD) != HAL_OK)
// {
// Error_Handler();
// }
/* USER CODE BEGIN RTC_Init 2 */
/* USER CODE END RTC_Init 2 */
}
I tried switching the RTC clock to an external quartz, but to no avail. Also in the initialization function, I tried to initialize the backup power supply (battery)