Greetings,
I have connected external crystal of 32.768 KHz to STM32F205RG for RTC time keeping purpose. I have also enabled RTC output on pin PC13. Below is my code for RTC Initialization ...
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_RTC_Init();
if (HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR1) != 0x32F2)
{
/* Configure RTC Calendar */
RTC_CalendarConfig();
}
else
{
/* Check if the Power On Reset flag is set */
if (__HAL_RCC_GET_FLAG(RCC_FLAG_PORRST) != RESET)
{
}
/* Check if Pin Reset flag is set */
if (__HAL_RCC_GET_FLAG(RCC_FLAG_PINRST) != RESET)
{
}
/* Clear source Reset Flag */
__HAL_RCC_CLEAR_RESET_FLAGS();
}
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
RTC_CalendarShow(aShowTime, aShowDate);
if(_set)
{
RTC_CalendarConfig();
_set = 0;
}
}
/* USER CODE END 3 */
}
This is the main code and code for RTC_CalendarShow and RTC_CalendarConfig is as below
static void RTC_CalendarConfig(void)
{
if(HAL_RTC_SetDate(&hrtc,&sDate,RTC_FORMAT_BCD) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
if (HAL_RTC_SetTime(&hrtc, &sTime, RTC_FORMAT_BCD) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
/*##-3- Writes a data in a RTC Backup data Register1 #######################*/
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR1, 0x32F2);
}
static void RTC_CalendarShow(uint8_t *showtime, uint8_t *showdate)
{
RTC_DateTypeDef sdatestructureget;
RTC_TimeTypeDef stimestructureget;
/* Get the RTC current Time */
HAL_RTC_GetTime(&hrtc, &stimestructureget, RTC_FORMAT_BIN);
/* Get the RTC current Date */
HAL_RTC_GetDate(&hrtc, &sdatestructureget, RTC_FORMAT_BIN);
/* Display time Format : hh:mm:ss */
sprintf((char *)showtime, "%2d:%2d:%2d", stimestructureget.Hours, stimestructureget.Minutes, stimestructureget.Seconds);
/* Display date Format : mm-dd-yy */
sprintf((char *)showdate, "%2d-%2d-%2d", sdatestructureget.Date, sdatestructureget.Month, 2000 + sdatestructureget.Year);
}
The problem is after like 4 hours of run rtc is ahead approx 2 seconds or more. How to solve this problem ?
The calibration output on pin PC13 gives me perfect 512 Hz wave as i have verified on oscilloscope. The same code is running prefectly fine on NUCLEO-F207ZG board.
