# Excess current consumption in ultra low power mode?

**URL:** <https://mangoh.discourse.group/t/excess-current-consumption-in-ultra-low-power-mode/573>\
**Category:** mangOH Green\
**Created:** [June 12, 2017, 9:59pm UTC](https://mangoh.discourse.group/t/excess-current-consumption-in-ultra-low-power-mode/573 "2017-06-12T21:59:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![fkoran](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/fkoran/32/218_2.png) [@fkoran](https://mangoh.discourse.group/u/fkoran)\
**Post date:** [June 12, 2017, 9:59pm UTC](https://mangoh.discourse.group/t/excess-current-consumption-in-ultra-low-power-mode/573/1 "2017-06-12T21:59:50Z")

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I have a Mangoh Green board that I’m using to evaluate the wp-series modules for power consumption

Idle, with SW401.8 active, the radio off, and devMode disabled, I measure 24mA across the CN1204 power supply selection jumper.

When I enter le\_ulpm\_ShutDown(), current drops to 10mA.

The WP8548 technical reference suggests that I should see \<1mA in ultra low power mode.  
Is there a hardware or software tweak needed to see that low current draw?

Here’s my configuration:

root@swi-mdm9x15:~# legato version  
16.10.3\_7776bb75a488e0db67b0d24975b46dd0\_modified

root@swi-mdm9x15:~# cm info  
Device: WP8548  
IMEI: 359377060015772  
FSN: LL604200091305  
Firmware: SWI9X15Y\_07.12.09.00 r34123 CARMD-EV-FRMWR1 2017/04/26 23:34:19  
Bootloader: SWI9X15Y\_07.12.09.00 r34123 CARMD-EV-FRMWR1 2017/04/26 23:34:19  
priIdPn: 9905383  
priIdRev: 01.07  
skuId: 1102816

Here’s a the log output from entering ultra low power mode

Jan 6 00:09:52 swi-mdm9x15 [user.info](http://user.info) Legato: INFO | helloWorld[1319]/helloComponent T=main | helloWorld.c \_helloComponent\_COMPONENT\_INIT() 8 | Set timer to 10 second  
Jan 6 00:09:52 swi-mdm9x15 user.debug Legato: DBUG | helloWorld[1319]/framework T=main | le\_ulpm\_client.c le\_ulpm\_ShutDown() 752 | Sending message to server and waiting for response : 0 bytes sent  
Jan 6 00:09:52 swi-mdm9x15 user.err kernel: [266.604608] qup\_i2c qup\_i2c.0: QUP: I2C status flags :0x1300c8, irq:187  
Jan 6 00:09:52 swi-mdm9x15 user.err kernel: [266.604700] qup\_i2c qup\_i2c.0: I2C slave addr:0x3a not connected  
root@swi-mdm9x15:~# Jan 6 00:09:55 swi-mdm9x15 user.debug SimpleRIL[1323]: [SIMPLE\_RIL\_INTEGRITY]  
Jan 6 00:09:55 swi-mdm9x15 user.debug SimpleRIL[1323]: simple ril init complete  
Jan 6 00:09:55 swi-mdm9x15 user.debug SimpleRIL[1323]: [SIMPLE\_RIL\_INTEGRITY]  
Jan 6 00:09:55 swi-mdm9x15 user.debug SimpleRIL[1323]: simple ril NW reg init complete  
Jan 6 00:09:55 swi-mdm9x15 user.debug SimpleRIL[1323]: SUCCESS (UNCONDITIONAL)  
root@swi-mdm9x15:~# packet\_write\_wait: Connection to 192.168.2.2 port 22: Broken pipe

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<div class="post-metadata">

**Author:** ![Raf](https://avatars.discourse-cdn.com/v4/letter/r/848f3c/32.png) [@Raf](https://mangoh.discourse.group/u/Raf)\
**Post date:** [June 13, 2017, 12:12am UTC](https://mangoh.discourse.group/t/excess-current-consumption-in-ultra-low-power-mode/573/2 "2017-06-13T00:12:46Z")

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Hi @fkoran,

There’s an application note on measuring current consumption in ULPM on mangOH. Hardware mods are required.

[https://source.sierrawireless.com/resources/airprime/application\_notes\_and\_code\_samples/airprime\_wp\_ulpm\_power\_measurement\_application\_note/](https://source.sierrawireless.com/resources/airprime/application_notes_and_code_samples/airprime_wp_ulpm_power_measurement_application_note/)

Additional considerations:

1. POWER\_ON\_N (SW401.1) should be OFF (switch open) to achieve the lowest power consumption in ULPM.  
Note that the module needs POWER\_ON\_N to be ON after power is applied for the module to boot.  
Once booted, it can be switched to the OFF position to improve power consumption even further.

2. Ensure `autosleep` is enabled - should be by default unless you’ve modified/disabled the script.

3. Disconnect the USB OTG cable to allow the module to enter USB-SS mode.

Raf

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<div class="post-metadata">

**Author:** ![fkoran](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/fkoran/32/218_2.png) [@fkoran](https://mangoh.discourse.group/u/fkoran)\
**Post date:** [June 15, 2017, 9:50pm UTC](https://mangoh.discourse.group/t/excess-current-consumption-in-ultra-low-power-mode/573/3 "2017-06-15T21:50:55Z")

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Thanks, that’s exactly what I was looking for