# Ultra low power mode WP76xx

**URL:** <https://forum.sierrawireless.com/t/ultra-low-power-mode-wp76xx/12903>\
**Category:** WP Series\
**Created:** [June 15, 2018, 6:59am UTC](https://forum.sierrawireless.com/t/ultra-low-power-mode-wp76xx/12903 "2018-06-15T06:59:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![abalzano](https://avatars.discourse-cdn.com/v4/letter/a/e68b1a/32.png) [@abalzano](https://forum.sierrawireless.com/u/abalzano)\
**Post date:** [June 15, 2018, 6:59am UTC](https://forum.sierrawireless.com/t/ultra-low-power-mode-wp76xx/12903/1 "2018-06-15T06:59:57Z")

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Hi everyone  
I try to start the following application to test ultra low power mode on wp76xx module, here the code  
void SwitchToLowPowerMode(void)  
{  
LE\_INFO("\*\*\*\*\*\*\*\*\*\*\*\*\*\* START ULTRA LOW POWER MODE \*\*\*\*\*\*\*\*\*\*\*\*\*\*");

// Boot after 1000 second of shutdown.  
LE\_ERROR\_IF(le\_ulpm\_BootOnTimer(1000) != LE\_OK, “Can’t set timer as boot source”);

// Boot if GPIO36 voltage level is high.  
LE\_ERROR\_IF(le\_ulpm\_BootOnGpio(36, LE\_ULPM\_GPIO\_HIGH) != LE\_OK, “Can’t set gpio36 as boot source”);

// Boot if GPIO38 voltage level is low.  
LE\_ERROR\_IF(le\_ulpm\_BootOnGpio(38, LE\_ULPM\_GPIO\_LOW) != LE\_OK, “Can’t set gpio38 as boot source”);

// Initiate shutdown.  
LE\_ERROR\_IF(le\_ulpm\_ShutDown() != LE\_OK, “Can’t initiate shutdown”);  
}

But when le\_ulpm\_ShutDown() is called i get an error that correspond to result LE\_NOT\_POSSIBLE.  
Than i try to enable manually this mode by do the following commands:

cd /sys/module/swimcu\_pm/boot\_source/  
echo 100 \> timer/timeout  
echo 1 \> enable

Than the board is shutdown and after 100s exit from low power mode. I measure the power consumption and doesn’t change. Can anyone tell me what i’m wrong?

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**Author:** ![mlw](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/mlw/32/3706_2.png) [@mlw](https://forum.sierrawireless.com/u/mlw)\
**Post date:** [June 15, 2018, 7:02am UTC](https://forum.sierrawireless.com/t/ultra-low-power-mode-wp76xx/12903/2 "2018-06-15T07:02:00Z")

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Hi,

I would suggest posting this sort of question to the legato forum rather than here as there are more firmware developers who go there and will be more able to answer questions like this.

> **[Legato Forum](https://forum.legato.io/)**
>
> Visit legato.io for more information

Regards

Matt

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**Author:** ![abalzano](https://avatars.discourse-cdn.com/v4/letter/a/e68b1a/32.png) [@abalzano](https://forum.sierrawireless.com/u/abalzano)\
**Post date:** [June 18, 2018, 9:46am UTC](https://forum.sierrawireless.com/t/ultra-low-power-mode-wp76xx/12903/3 "2018-06-18T09:46:56Z")

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Hi Matt,  
Thank you for your reply, i have already make a post on legato forum and mangoh forum.

Regards  
Angelo