STM32F207 lock up in Standby

[nibbly78]

Posted on September 19, 2016 at 16:47

Hi, I have some code running when on a certain condition, it goes into standby.

I have pre-configured the RTC to wake the processor after 30 seconds. Everything works as expected except if cycle the power whilst its in standby.

If i remove supply for a 1 second and re-apply, the processor is stuck in standby and the only way to get it out is to remove the supply for about 3 seconds then re-apply. 

I get that its probably due to so little current being drawn that supply does not collapse quick enough but should this crash the RTC alarm and prevent a reset?

I have tried external and internal RTC oscillator configurations  and I have tried turning on the Brown out but I can still get the processor to lock up in standby.

Other than fitting an external brownout IC is there a way to prevent these lock ups?

Thanks

[Tesla DeLorean]

Posted on September 19, 2016 at 17:32

Are you sure it is not just stuck in your code somewhere? I'd probably look to set some GPIO/USART in the ResetHandler, and check for unbounded loops in the SystemInit(), and early main()

[nibbly78]

Posted on September 20, 2016 at 17:12

I'm pretty sure it's stuck in standby and not in a while loop because the current being drawn is nearly 0 (which is the same as standby current consumption)

[waclawek.jan]

Posted on September 20, 2016 at 23:26

Tell us more on how the power and ground pins are connected.

JW