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LSI for IWDG (is resolved)

veacheslavkris
Associate II
Posted on November 21, 2016 at 17:41

Hi, in order to use IWDG should I manualy starting LSI or LSI will start automatically ?

I am going to use CMSIS. 

Thank you.
3 REPLIES 3
valentin
Senior
Posted on November 21, 2016 at 20:13

You can always check the status of LSI in the RCC register (check ref manual).

And if it's not started where you need it, start it yourself.

Posted on November 22, 2016 at 11:21

We don't know what STM32 model are you using, but if you look into the respective RM's RCC chapter, chances are that there's ''watchdog clock'' or similar sub-chapter, with a text like this (taken from RM0091):

If the Independent watchdog (IWDG) is started by either hardware option or software access, the LSI oscillator is forced ON and cannot be disabled.

I've played a bit with a 'F031 and found that enabling IWDG without prior enabled LSI causes RCC_CSR.LSIRDY being set (without affecting RCC_CSR.LSION), and if RCC_CIR.LSIRDYIE was set previously, RCC_CIR.LSIRDYF gets set too. This is

https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/STM32F0xx%20findings&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=34

behaviour than when ADC autoswitches the HSI14 oscillator...

veacheslavkris
Associate II
Posted on November 22, 2016 at 12:30

Thank you. I think the question now may be closed as resolved.