RTC Fault

Dear Team,

R7FS5D57C3A01CFP MCU- is used.. We are experiencing a problem with the RTC in one of our products. When we set the RTC, there is no drift, and it counts correctly; however, two issues occur:

  1. When we set the time to 11:58, it should update to 12:00 after 2 minutes, but instead, it resets to 00:00.
  2. The date does not change.

We have verified that there is no issue with the crystal; the frequency measurements are shown in the images below. Despite this, we replaced the crystal, but the issue still persists.

I would appreciate your help in understanding the cause of this issue and finding a solution. Thank you.

Best Regards

  • As mentioned if the value in an RTC register after a reset is given as x (undefined bits) in the list, it is not initialized by a reset. When RTC enters the reset state or a low power consumption state during counting operations, for example while the RCR2.START bit is 1, the year, month, day of the week, date, hours, minutes, seconds, and ***-Hz counters continue to operate. 

    So the option should be configured according to the user application

    When the "RTC hardware in open() call" value to "No", the following if-statement will not be executed:

    The r_rtc_set_clock_source function clears START bit to 0 and sets the hour mode bit:

    It is a bit strange the problem is this one device, but does every RTC API return with SSP_SUCCESS ?

  • Hello,

    We have not seen this error in more than 100 batteries we have used before. Is there a possibility that this error is product-based, i.e. hardware-related? Other MCU's HR24 is 1 from the beginning. Is there any  possibility HR24 register sets 0 during mass production. If the configuration section is selected to yes to change HR24, will we see a problem related to rtc working?. 

    Best Regards.

  • I check the RTC API  return values. The RTC APIs and responses used in the initialize section are shared in the picture below. I think there is no problem in the API values.

  • What SSP version do you use ?

    Does this error still happen ?

    Is the above code with the option set to Yes or No ?

    If you set this option to 'Yes', the only thing that it changes is that the RTC clock source and registers will be initialized every time after reset. Is this a problem for you ?