HAL RTC SetDate Bug or some another way to do??

[Joshin Joy]

Posted on February 23, 2017 at 10:49

I am using STM32F103 in my new application. I have used STM32Cube to generate my code including Internal RTC. My

problem is that the time is ok saved when reseted but date is always reset. when i inspected the code i found that the HAL_RTC_SetDate() function is not setting the RTC_CNTH and RTC_CNTL registers appropriately. Is it a bug or is there any other way of doing this. when we add day shouldn't  the RTC_CNTH and RTC_CNTL added with (24hrs x 60 Mins x 60 Secs) this is not happening.#cube-mx #hal-library

[lhofstaetter9]

Posted on June 02, 2017 at 09:30

For me its the same. I use RTC_SetDate and RTC_SetTime to set the date and the time. After that I use RTC_GetDate and RTC_GetTime to read the date and the time. The time works, but the date is still the same. If I do then a system reset by pressing the reset button, the date can be read properly. So writing date and time seems to work. But reading does not work.

[Tuttle.Darrell]

Posted on June 02, 2017 at 13:33

I don't know if this is related or not:

I had an issue a few years ago with the STM32F407 (using SPL). After changing the date, RTC_GetDate was not returning the correct date for sometimes upwards of 100 attempts (my test was to read and display the time and date every second). I never resolved the cause, but I came up with a rework; if I first called RTC_GetTime BEFORE calling RTC_GetDate, all was well. RTC_WaitForSynchro did not correct the problem.

[samuel23]

Posted on June 06, 2017 at 14:48

I had the same problem (on STM32L152)... and I found this subject last week...

I tried to invert the call to have 

RTC_GetDate() AFTER 

RTC_GetTime()... and I got good results. As a feeling, I guess it solved the problem......... h

oping it is not a coincidence!

[waclawek.jan]

Posted on June 06, 2017 at 15:12

This is a feature. Read the fine manual, RTC chapter, Reading the calendar subchapter:

 To ensure consistency between the 3 values, reading either RTC_SSR or

RTC_TR locks the values in the higher-order calendar shadow registers until RTC_DR isread.

I believe this is mentioned even in the Cube documentation (I am not going to provide pointers to that).

JW

[OleksiiUA]

I myself spent the whole day to figure it out. Implemented the clock using third-party functions. And only in the evening while analyzing code HAL_RTC_GetTime() did it come to me. The function counts only one day days_elapsed in a circle and counts days. ->> 

/* Update date */

RTC_DateUpdate(hrtc, days_elapsed);

They need to be stored in another memory, for example, in backup registers.