STM32F1 Clock/Calendar BUG

[tetj]

Posted on April 24, 2014 at 15:08

Hello, I noticed a problem in the software implementation of STM32F1 's clock/calendar. If the device is switched off for a long time (>= 255 days) it will enter infinite loop inside  CheckForDaysElapsed() (which is inside RTC_Configuration() function) because the for(;;) loop variable is only 8bits in size. I replaced several microcontrollers before finding this as I thought they were faulty.

Has anyone encountered this issue ?

[Amel NASRI]

Posted on April 28, 2014 at 16:03

Which software implementation are you speaking about?

-Mayla-

[tetj]

Posted on April 28, 2014 at 22:08

The one from

http://www.st.com/web/catalog/tools/FM147/CL1794/SC961/SS1743/PF257855

. It is for STM32F1 series only.

[Tesla DeLorean]

Posted on April 28, 2014 at 23:21

Yes, there appear to be issues with that, and frankly I don't care for that approach to calendering. I built a scheme using a 32-bit second value from epoch (136 years), and computed the date/time when required. A linear view of time is best expressed in seconds, not human centric dates.

Rule#1 For Third-Party calendering solutions : They are usually broken in subtle ways, and the time required to validate them would exceed the time to write correctly from scratch.

[tetj]

Posted on April 29, 2014 at 00:05

Couldn't agree more Clive, good thing I only used the lib for one project. I then switched to UNIX time format too. As you said it is pretty straightforward.