STM32F042 RTC wont start

[lmill.1]

I seem to be unable to get the RTC to start. I can set the time, and read from it, but it doesn't increment.

I have tried using the external and internal oscillator, neither have been successful.

Everything has been set up with CubeMx, and I have used the RTC before on an STM32L0 micro with no issue, comparing it to my old code I cant see what I am doing differently.

I have attached the relevant parts of the code, if you know what I am missing please let me know.

Thanks,

Luke

static void MX_RTC_Init(void)
{
 
  RTC_TimeTypeDef sTime;
  RTC_DateTypeDef sDate;
 
    /**Initialize RTC Only 
    */
  hrtc.Instance = RTC;
if(HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR0) != 0x32F2){
  hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
  hrtc.Init.AsynchPrediv = 127;
  hrtc.Init.SynchPrediv = 255;
  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(__FILE__, __LINE__);
  }
 
    /**Initialize RTC and set the Time and Date 
    */
  sTime.Hours = 0x0;
  sTime.Minutes = 0x0;
  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(__FILE__, __LINE__);
  }
 
  sDate.WeekDay = RTC_WEEKDAY_MONDAY;
  sDate.Month = RTC_MONTH_JANUARY;
  sDate.Date = 0x1;
  sDate.Year = 0x0;
 
  if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BCD) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }
 
    HAL_RTCEx_BKUPWrite(&hrtc,RTC_BKP_DR0,0x32F2);
  }
 
}
/* USER CODE BEGIN PV */
RTC_TimeTypeDef sTimeGet;
RTC_TimeTypeDef sTimeSet;
 
/* Private variables ---------------------------------------------------------*/
 
/* USER CODE END PV */
 
void updateTime(void){
	//RTC_TimeTypeDef sTimeGet;
	//RTC_TimeTypeDef sTimeSet;
	HAL_RTC_GetTime(&hrtc, &sTimeGet, RTC_FORMAT_BIN);
	seconds = sTimeGet.Seconds;
	minutes = sTimeGet.Minutes;
	hours = sTimeGet.Hours;
 
	if(hours>12){
		hours = 0;
		sTimeSet.Hours = hours;
		HAL_RTC_SetTime(&hrtc, &sTimeSet, RTC_FORMAT_BIN);
	}
}

[waclawek.jan]

When you step through code, is it the same binary as when running? Or, are you using a Debug/Release mechanism to compile with different optimization levels? If called from interior, is the variable where you store time tagged as volatile?

JW

[lmill.1]

The sTimeSet is global, lines 49 and 50 of the snippet............. i have working reference code that i also mentioned in the original post, and i did use cubemx to generate this code, which i also mentioned in the original post..............

I got it working though, as you can see in the other thread we had going it was only working if i stepped through the code. The problem was I was running my set time function in my main while loop that I had forgotten to move after debugging so it was writing the time and writing over the read results before they could be used.

thanks for your input.

[lmill.1]

Got it working, my setTime function was in my main loop and overwriting the values before they could get used. Thanks for your advice.