Reduce nRF52832 current during connection

[nrbrook]

We've built a custom board, at power off current is 1-2uA and when connected average current is ~4.7mA. Internal DCDC is enabled, this shaved off >2mA. Other than reducing TX power, which we have yet to experiment with, is there any other way to reduce the current whilst connected?

Thanks

[Jared]

Hi,

• How are the GPIOs configured for interrupts and what event are you using? PORT or IN event?
• What is the supply voltage at?
• Are you using any other peripheral in your project? Some peripherals might consume current if they are not un-initialized properly. 
• Can you confirm by using the debugger and pausing your application that it regularly enters the IDLE  __WFE() loop in sd_app_evt_wait()? Also, note that softdevice applications has to be restarted each time the CPU is halted during debugging. Otherwise the application will assert when you try to resume the application. 
• Any timers or peripherals that you use where you write directly to the registers instead of using our drivers? 

nrbrook said:

Is there any way to profile what is using CPU time?

If you're using the logger module and the pwr_mgmt lib then you try enabling NRF_PWR_MGMT_CONFIG_DEBUG_PIN_ENABLED in your sdk_config.h file. 

regards

Jared 

[nrbrook]

After a lot of trial and error I determined it was caused by this bug:

https://devzone.nordicsemi.com/f/nordic-q-a/80636/nrfx_saadc_abort-in-saadc-api-v2

now the average current is ~50uA which is in line with online power profiler.

Thanks for your help, the power management CPU usage monitor was particularly helpful.