Problem reading the RTC calendar after re writing it.

[Santiago_Deliotte]

Hello. I'm trying to make a code to show some menús (configuration and user menús) in a LCD screen, but something goes wrong when I try to write the year, and read it later, from the RTC calendar registers.

My main code begins with the cube MX function that sets a initial value to all the RTC calendar fields:

sTime.Hours = 0x09;
  sTime.Minutes = 0x30;
  sTime.Seconds = 0x00;
  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_FRIDAY;
  sDate.Month = RTC_MONTH_MARCH;
  sDate.Date = 0x31;
  sDate.Year = 0x23;
 
  if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BCD) != HAL_OK)
  {
    Error_Handler();
  }

Later, I can configure the time and date, using some enums to do it more human, in the exit section of a configuration menú:

if (new_exit == 1)
    {
        date_final.Date = day_enum;
        date_final.Month = month_enum;
        date_final.Year = year_enum;
 
        HAL_RTC_SetDate(&hrtc, &date_final, RTC_FORMAT_BIN);
 
        time_final.Hours = hour_enum;
        time_final.Minutes = minute_enum;
        time_final.Seconds = second_enum;
 
        HAL_RTC_SetTime(&hrtc, &time_final, RTC_FORMAT_BIN);
 
        new_entry = 1;
        new_exit = 0;
    }

For example, I can set the date = 31, month = 03, year = 23, and so on...

And finally, in an user menú, I wanted to show the time and date, reading the calendar again, using the following code:

void fm_calendar_get()
{
    __HAL_RTC_WRITEPROTECTION_DISABLE(&hrtc);
    HAL_RTC_WaitForSynchro(&hrtc);
    __HAL_RTC_WRITEPROTECTION_ENABLE(&hrtc);
 
    HAL_RTC_GetTime(&hrtc, &sTime, RTC_FORMAT_BIN);
    HAL_RTC_GetDate(&hrtc, &sDate, RTC_FORMAT_BIN);
}

But when I read the date, the year is always wrong, it's different than the year I selected before.

I think it is because of the BCD representation of the RTC, but I really don't know how to solve it.

I can give the whole code if it's needed, but it is really a mess, and you will need to configure some buttons to recreate the error...

[waclawek.jan · Accepted solution]

Initialize the whole struct used to write time and date.

Cube is open source. Single step it in debugger to see, what is happening.

JW

[Santiago_Deliotte]

You are totally right, it's the second time someone show me that web page, and I think it's fantastic.

Thanks a lot.