stm32f4 __wfi

Jython googcheng at gmail.com
Wed Apr 24 00:35:14 UTC 2019


yes, I need to do low power for stm32f4
will this line work __asm__ volatile ("wfi");?


On Tue, Apr 23, 2019 at 10:28 PM Christian Mauderer <
christian.mauderer at embedded-brains.de> wrote:

> Am 22.04.19 um 09:47 schrieb Jython:
> > HI, ALL!
> > wfi
> http://www.keil.com/support/man/docs/armcc/armcc_chr1359125004400.htm
> > how can i call the arm __wfi?
> >
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>
> Hello Jython,
>
> WFI is an assembler instruction. The Keil wrapper isn't available in
> gcc. I know of no direct replacement. Most likely you need a gcc inline
> assembly for that.
>
> May I ask why you would need "wfi"? If you use a operating system, the
> system typically handles such low level stuff for you. The only
> application that springs to mind for that instruction is overwriting the
> idle loop to save energy.
>
> Best regards
>
> Christian
>
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