I’ve loaded the Power_Manager example. When sleeping the F7v2 appears to draw 31.2mA. Is there a way to reduce this further? I am measuring between the battery and the f7 on the positive wire.
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I’d love to see sleep in the uA range. That would significantly help my battery powered IoT project.
Assuming I’m reading the STM32F7 docs correctly, this should be possible:
https://www.st.com/resource/en/product_training/STM32F7_System_PWR.pdf
https://wiki.st.com/stm32mcu/wiki/Getting_started_with_PWR
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It appears that nuttx has support for the Stop mode and the Standby mode. What does it take to get these available in Meadow.OS? Also when in sleep mode do the other co processors go to sleep? The document above claims 18 mA in sleep mode but I was seeing 31 mA. That seems a little more than just power loss due to voltage converters. Seems like other components on the board aren’t sleeping.
Is it at all possible to wake up the device using a hardware interrupt (pin) in stead of using a timer?
I need to place my IoT application into a permanent sleep state, and only wake it up when the user presses a button.
@michalsteyn It does not look like this is possible with the current version (1.3) of Meadow.Core. The STM32F7 does have that ability and it appears to be available in Nuttx OS (stm32_pmsleep.c), just not yet implemented in Meadow.Core.
If your project is anything like mine you’ll need a bigger battery than you think and/or a solar panel until Meadow fixes/adds other “sleep” options. At my tests of 32mAh power usage during sleep, that would only get a few days on a 3000mAh battery.
I’m curious how the Clima v3 power usage looks. It appears they increased the size of the solar panel required at some point.
https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-battery-life
