RTC ALARM + PA0 Wakeup from standby, problem

Marco1 · ‎2017-08-16

Posted on August 16, 2017 at 18:45

I have a problem with STM32F415RG....

My project has two system of wakeup from standby, first is PA0 pin and other RTC Alarm.

If i put a single way of wakeup, like only PA0 wakeup work, if i put only RTC ALARM wakeup work, when i put both, not work...

I make many test:

When i put a alarm 30 seconds after standby, and i move the PA0 pin before the ALARM start, wakeup from pin work

When i put a alarm 30 seconds after standby and i wait the RTC ALARM, the system not start and not start anymore also from PA0 pin

Someone has same problem ?

Sorry for my english

STOne-32 · ‎2017-08-16

Posted on August 16, 2017 at 22:17

Dear marco,

See our Errata 2.1.5 and apply the workaround.

Cheers,

STOne -32

Marco1 · ‎2017-08-16

Posted on August 16, 2017 at 23:01

I have already used the workaround but not work, anyway the result is the same.

Can you show me a little working example with ALARM A + PA0 Wake up with External Crystal 32768 ?

Marco1 · ‎2017-08-17

Posted on August 17, 2017 at 18:05

I found the problem....when enter on standby, i have PA0 pin high.....

STOne-32 · ‎2017-08-17

Posted on August 17, 2017 at 18:54

Hi Marco,

Nice to see you solved it. Good job.

Cheers,

STOne-32.

Marco1 · ‎2017-08-19

Posted on August 19, 2017 at 17:06

But i suggest to correct the datasheet, because inside the only note is:

'Note: An additional wakeup event is detected if the WKUP pin is enabled (by setting the EWUP bit) when the WKUP pin level is already high.'

But you don't say that RTC Alarm not work if pa0 pin is high during WKUP pin enabling.

So if you enable RTC ALARM, push high pa0_pin and enable it throught EWUP, RTC ALARM will not work.

Please check it