app_timer high current consumption

[kisvegabor]

I'm trying to reduce the power consumption of my custom board with nrf52822.

With this code I get 93 uA:

int main(void)
{
   while(1) {
        __WFE();
        __SEV();
        __WFE();
   }
}

If I enable only the app_timer I get 533 uA:

int main(void)
  {

  nrf_pwr_mgmt_init();
  app_timer_init();
  
   while(1) {
        __WFE();
        __SEV();
        __WFE();
   }
}

I'm using "RC" "..._LF_SRC" in "sdk_config.h".

What I'm doing wrong? 

app_timer is not really required in my appliaction but I found that it is used in "conn_params_init".

[Simonr]

Hi

The app_timer uses the high frequency clock. So if you keep the app_timer running, it will like most peripherals using the high frequency clock applications, result in approximately 0.5mA current consumption. To reduce this while keeping time, try using the RTC. See the app timer library for how to do this.

Best regards,

Simon

[kisvegabor]

Hi,

Thank you for the quick response.

On the linked page I didn't find anything about how to use the RTC for this purpose. However, it says "The timer library (also referred to as app_timer) enables the application to create multiple timer instances based on the RTC1 peripheral." So it already uses RTC1? Have I missed something?