nrf_delay_ms consuming too much power

[saiteja]

hi, I am working on nrf52 sdk11 and s132, when I am using ble_app_uart example on my custom board I used nrf_delay_ms(10000) i.e 10 seconds when i observe current consumption is 4mA. what is the reason it is consuming too much current? but after that delay of time, it is coming back to initial current consumption i.e 50microAmp

Thanks in Advance,

[endnode]

Not so much surprising i you see what's inside the function (just busy loop of NOP instructions;) This should never be used outside debug code, for all the rest proper (RTC based) timer with interrupt wake-up (event handler) is the way how to measure time on ARM Cortex-M SoCs...

[Jørgen Holmefjord]

Hi,

nrf_delay_ms() is implemented as a series of NOP instructions, meaning that the CPU active but not performing any operations. The increased current you are seeing is the CPU current. In general, it is not recommended to use busy-wait for long delays. You should instead setup a timer/RTC to wake the chip after the desired time, and put the chip into system on sleep mode. This will turn off CPU, saving much power.

Best regards,

Jørgen