STM32F4 Standby Mode greater than 36 hours

[doebber2]

Posted on December 09, 2016 at 13:01

Hi!

I want to put my STM32F4 in StandBy mode for more then 36 hours.

At the moment I use the RTC wakeup interrupt but the maximum time is 0x1FFFF seconds (36 hours).

Is this possible to set a greater value?

regards Marc

[Lawliet KG · Accepted solution]

Posted on December 09, 2016 at 19:47

Dear Marc,

The wakeup unit clock is configured through the WUCKSEL[2:0] bits of RTC_CR register.

Three different configurations are possible:              â—� Configuration 1: WUCKSEL[2:0] = 0xxb for short wakeup periods

              â—� Configuration 2: WUCKSEL[2:0] = 10xb for medium wakeup periods

              â—� Configuration 3: WUCKSEL[2:0] = 11xb for long wakeup periods

The maximum interrupt time provided by configuration 2 is 131072 seconds (a little bit more than 36h), so you should use configuration3. This configuration enables the MCU to wake up from the standby mode with a maximum delay of 4194304 s (more than 48 days).

All those information are already available on the application note AN3371.

Wish this could help you.

If this answers your request, please press 'correct' 

:)

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Best regards,

Lawliet.

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