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How I can distinguish, ALARM A or ALARM B waked up STM32L053 from Standby mode?

Alexey Ostrejkovsky
Associate II

My controller can be waked up from Standby mode by Alarm A or Alarm B: Alarm A every day and Alarm B every minute. Are there any flags (or another means) to know, what event (Alarm A or B) was cause of the waking? That is the problem, because all registers (excluded PWR_CSR and RTC Backup) "dying" after MCU entering in Standby mode...

1 ACCEPTED SOLUTION

Accepted Solutions
TDK
Guru

> Are there any flags (or another means) to know, what event (Alarm A or B) was cause of the waking?

Read the current RTC value and determine if it's consistent with an every minute or every day wakeup time.

If you feel a post has answered your question, please click "Accept as Solution".

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2 REPLIES 2
TDK
Guru

> Are there any flags (or another means) to know, what event (Alarm A or B) was cause of the waking?

Read the current RTC value and determine if it's consistent with an every minute or every day wakeup time.

If you feel a post has answered your question, please click "Accept as Solution".
Alexey Ostrejkovsky
Associate II

Many thanks!

It looks like it will have to be done... STM32L053 has no any alarm flags, which can survive the standby mode.