STM32 Sleep

SARTHAK KELAPURE · ‎2018-01-29

Posted on January 29, 2018 at 13:02

What is the best way to put STM32L0 micro-controllers to sleep for limited time duration(preferably using RTC)?

#stm32l0 #stm32-sleep

Andrew Neil · ‎2018-01-29

Posted on January 29, 2018 at 13:14

There is no such thing as 'best' - it all depends on your particular requirements.

It is a tradeoff between

current consumption while in sleep;
functionality while in sleep;
available wakeup triggers;
time taken to 'wake up' from sleep;
amount of reconfiguration required to enter & exit sleep;
etc...

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

SARTHAK KELAPURE · ‎2018-01-29

Posted on January 29, 2018 at 13:18

Well, in that case, I would like to wake the controller on an RTC timeout and would like to have low power consumption(not the least, functionality is priority). Is this possible?

Andrew Neil · ‎2018-01-29

Posted on January 29, 2018 at 13:41

So have you looked at the Datasheet and Reference Manual - they list & describe the available 'sleep' modes ...

The STM32L0x2 Reference Manual, at least, has code examples at the end ...

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

Tesla DeLorean · ‎2018-01-29

Posted on January 29, 2018 at 18:08

Pretty sure the LRWAN implementation is illustrative of the RTC being used as the primary timebase, placing the device into SLEEP state(s)

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Andrew Neil · ‎2018-01-29

Posted on January 29, 2018 at 18:19

Yes, it is - though rather a lot to wade through just for an example of SLEEP ... !!

:(

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

Tesla DeLorean · ‎2018-01-29

Posted on January 29, 2018 at 18:21

But the mechanics are at least fully explored. And the OP was using the LoRa L0 code previously.

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Up vote any posts that you find helpful, it shows what's working..

Andrew Neil · ‎2018-01-29

Posted on January 29, 2018 at 18:37

Oh yes - so he did:

https://community.st.com/community/stm32-community/blog/2017/04/05/lora-discovery-kit?commentID=4845&sharpcomment-4845

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

SARTHAK KELAPURE · ‎2018-01-29

Posted on January 29, 2018 at 18:46

Even though my recent work has been on LoRa discovery board and on LoRa, I just wanted to know best possible way for STM32 controllers to go to sleep and wakeup. Also, right now I am still on LoRa stack and wish to best utilize the sleep options available.

Andrew Neil · ‎2018-01-29

Posted on January 29, 2018 at 18:54

Again, 'best' is meaningless - unless accompanied by a specific set of criteria by which to judge it.

If there was just one single 'best' option - why would the chip provide any others?

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.