[nuttx] STM32L4 : Stop2 mode exit using the Wakeup timer [1 Attachment]

[pm MIC [e-mail] [nuttx]]

Hello,


I wrote a small program (from the program example Hello) to test the low power stop2 mode and the exit of this mode on a STM32L476vg-Discovery evaluation board. The program switches to the mode but does not exit using the wakeup timer.
Note : If the Stop2 mode is replaced by the Standby mode, the exit is done correctly.
Program as an attachment
Thanks
Regards
PM

[[e-mail] [nuttx]]

Hi,

Would you have an example of using the low power stop2 mode and the wake up from this mode for an stm32l4 ?


Thanks


PM

[Alan Carvalho de Assis [e-mail] [nuttx]]

There is an configuration example to use NuttX's Power Management
using the STM32F4Discovery, but I never tested it:

configs/stm32f4discovery/pm

So, you could test it and post here case you find some issues, this
way we could to help you.

BR,

Alan

Post by ***@yahoo.com [nuttx]
Hi,
Would you have an example of using the low power stop2 mode and the wake up
from this mode for an stm32l4 ?
Thanks
PM

[[e-mail] [nuttx]]

I believe that the L4 is very different in this regard, but I have never worked with the L4 and I am not aware of anyone doing any power management work with that chip.

[Sebastien Lorquet [e-mail] [nuttx]]

hello

no work was ever done to support any low-power feature of the 32l4.

If you need it, you will have to contribute it, yes, in the NuttX power
management framework.

Sebastien

Post by ***@yahoo.com [nuttx]
Hi,
Would you have an example of using the low power stop2 mode and the wake up
from this mode for an stm32l4 ?
Thanks
PM

[[e-mail] [nuttx]]

Hello,

My need is the following (on a stm32l4 configuration): I must be able to switch the µc to stop2 mode and exit after 100ms to do an acquisition.


I don't see how to use the PM to do this. What is (or would be) the interaction between the pm_changestate method and the method stm32l4_pmstop2 (this method is not directly accessible) ?


Regards


PM

[Alan Carvalho de Assis [e-mail] [nuttx]]

Hi PM,

Entering and leaving the sleep mode waste power.

I think you need to double check it first, entering and leaving sleep
mode each 100ms could waste more energy than staying in normal mode.

Maybe you should consider running the MCU in a lower frequency. As I
recall there is a table in the STM32 datasheet (at least for STM32F4)
with its power consumption at different frequencies.

A strategy: stay in lower frequency during the samples acquisition,
then after you got i.e. 100 or more samples, scale up the MCU to
process the data, then return to lower frequency.

BR,

Alan

Post by pm MIC ***@yahoo.com [nuttx]
Hello,
My need is the following (on a stm32l4 configuration): I must be able to
switch the µc to stop2 mode and exit after 100ms to do an acquisition.
I don't see how to use the PM to do this. What is (or would be) the
interaction between the pm_changestate method and the method stm32l4_pmstop2
(this method is not directly accessible) ?
Regards
PM

[[e-mail] [nuttx]]

Hi Alan,


This process (100ms in stop2 + about 5ms for processing, frequency 4Mhz) was tested on a platform (prototype) with a ÎŒc STM32l4, without the NUTTX environment but directly with the _HAL API.

Consumption results are interesting.
And now, the idea is to test this process with Nuttx.



Regards


PM