problem with wakeup from stop mode

[kkkuba]

Posted on July 23, 2013 at 21:42

Hi, I've got some difficulties with wake uC up from stop mode. Firstly I copied example from Std Periph Library for STM32F103: it uses alarm from RTC to wake up. I implemented it and everything was OK. But next - I try to make the same in FreeRTOS - I change clock source for tick interrupt to RTC - alarms from RTC generate tick interrupts. I want to get into stop mode in idle hook function and wake up when alarm from RTC happens, but it doesn't work. I didn't change configuration of NVIC and EXTI. I'm clueless why...

Thanks for attention and help

[Nickname12657_O]

Posted on July 23, 2013 at 23:38

I would suggest to have a look at FreeRToS.org forum on this case, as it seems you made a configuration not compatible with the kernel tasks operation. as in Stop mode, all MCUs clocks are frozen and Idle task will stop as well.

[kkkuba]

Posted on July 24, 2013 at 13:29

Ok, thanks, I'll try.

But does stop mode affect the configuration and operation of the RTC? I think it doesn't, so this is only to ensure

[Nickname12657_O]

Posted on July 24, 2013 at 18:22

You are correct, RTC function is kept active.

Cheers,

STOne-32.

[Tesla DeLorean]

Posted on July 24, 2013 at 18:28

The RTC however does have a dependency on the VBAT supply, and only LSE is in the backup power domain (F1/F2/F4). LSI will not tick when the primary regulators turn off.

[Nickname12657_O]

Posted on July 24, 2013 at 19:01

Dear Clive,

Here we are in STOP mode, Only digital clocks are stooped, but  Power domains are kept powered by VDD and regulator is always active ( either in RUN or LP modes).

It seems the standalone example is working fine ( bare-metal)  , but only when FreeRTOS is added, there is an issue.  So I'm not suspecting Hardware, neither the device...

Ciao,

STOne-32.

[kkkuba]

Posted on July 24, 2013 at 20:09

Thanks for reply,

regards