Reduce current in Low power mode

RE: Reduce current in Low power mode

ovrebekk — Wed, 18 Mar 2020 09:34:25 GMT

Hi Mihir

I think you should initialize the buttons and LED's even if you're not using them, otherwise you could have issues with floating pins as I mentioned earlier.

For sleep timing you should use one of the RTC timers, as they will run at a much lower current than the TIMER modules.

The app_timer module in the SDK is also based on the RTC, and can be used to wake up the CPU at regular intervals while consuming only a couple of microamps in between.

Best regards
Torbjørn

RE: Reduce current in Low power mode

Mihir Chauhan — Tue, 17 Mar 2020 18:10:37 GMT

Hi Thank you for your quick response.

Below are code changes which I need to make.

In my while(1) loop function idle_state_handle() is getting called so, when there is no event CPU is in sleep mode only.

Low power mode is enabled by default so no need to set it explicitly.

I have used standard development kit for this demo. So, all BSP initialization is as per standard DK only.

I have not called bsp_init function. So, my GPIOs are not initialized as I don't need any GPIO configurations.

I want to run timer in sleep mode and wake up after specific time interval.

Can you please suggest how can I proceed ahead to reduce current to less than 50 uA.??

RE: Reduce current in Low power mode

ovrebekk — Mon, 16 Mar 2020 14:03:16 GMT

Hi Mihir

sd_app_evt_wait() is technically the right function to run, but when using the power management module you should use idle_state_handle() instead.

NRF_POWER_MODE_LOWPWR is the default power mode, so unless you have set it to something else you don't need to set it in the code.

When having issues with excessive current draw in sleep it is usually caused by incorrect GPIO configuration (leading to floating pins, or pins being pulled high or low), or some peripheral running in sleep that shouldn't be, such as a TIMER module.

I can't see any GPIO configuration in your code?

Are you using a standard DK, or a custom board?

Best regards
Torbjørn