ble_central_and_peripheral Power waste

[john.liu]

I use sdk15.0.close log.

config:

#define APP_ADV_INTERVAL                2000

#define SCAN_INTERVAL                   2000

#define SCAN_WINDOW                     0x0050

code:

main()

{

  clock_init();

    power_management_init();
    ble_stack_init();
    timers_init();
    buttons_leds_init(&erase_bonds);

    peer_manager_init();
    gap_params_init();
    gatt_init();
   conn_params_init();

   db_discovery_init();
   hrs_c_init();

    services_init();
  advertising_init();

    // Start execution.
    application_timers_start();
  erase_bonds=true;
  nrf_sdh_freertos_init(adv_scan_start, &erase_bonds);
  // Start FreeRTOS scheduler.
  vTaskStartScheduler();

}

What else can I do? Can reduce its power consumption.

[Susheel Nuguru]

Hi,

Can you do a quick experiment and try the same example without freertos.

You only need to change to files in your project. instead of app_timer_freertos.c use app_timer.c and instead of nrf_sdh_freertos.c use nrf_sdh.c.

replace last threelines of your main.c with below

// Enter main loop.
for (;;)
{
 idle_state_handle();
}

and measure the power again.

You will then know how much difference in power you have in baremetal vs rtos app.

I am guessing about 80uA. If it is way more, then something is wrong.

[john.liu]

hi:

 Thank you for your support.Without freertos, the power consumption decreases.What should I do if I need to use FreeRTOS.

[Susheel Nuguru]

how much was your exact same application without FreeRTOS?

[john.liu]

Without freeRTOS.Upper figure Electric current 450 uA.

[Susheel Nuguru]

so about 50uA increase with FreeRTOS, seems about right.

The FreeRTOS kernel needs to executed every tick to do some book keeping which consumes power. 50uA seems like a very reasonable amount for an kernel to maintain its book keeping.

[john.liu]

No.I mean, the current using freeRTOS is 1mA, and the current without freetros is 450uA.

At the same time, I tested the current of ble_app_hrs and ble_app_hrs_freertos are 170uA and 1mA, respectively.

nRF5_SDK_15.0.0_a53641a\examples\ble_peripheral\ble_app_hrs:

nRF5_SDK_15.0.0_a53641a\examples\ble_peripheral\ble_app_hrs_freertos:

[Susheel Nuguru]

That does not sound correct. 

Can you please test the FreeRTOS part again by removing the line number 239 and 248 in nRF5_SDK_15.0.0_a53641a\nRF5_SDK_15.0.0_a53641a\external\freertos\portable\CMSIS\nrf52\port_cmsis_systick.c

// Comment or remove "#if 0" line
// #if 0  // With FreeRTOS sd_app_evt_wait increases power consumption with FreeRTOS compared to _WFE (NRFFOSDK-11174) 
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
                uint32_t err_code = sd_app_evt_wait();
                APP_ERROR_CHECK(err_code);
            }
            else
#endif
// #endif // (NRFFOSDK-11174)  <- comment or remove this line

[john.liu]

hi:

I tested hrs project.

Modify:

#if 1  // With FreeRTOS sd_app_evt_wait increases power consumption with FreeRTOS compared to _WFE (NRFFOSDK-11174)
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
                uint32_t err_code = sd_app_evt_wait();
                APP_ERROR_CHECK(err_code);
            }
            else
#endif

test result:

The current dropped by 800uA.

[Susheel Nuguru]

yeah, we have some investigation to do there, that is why i created that ticket 11174. So now that it dropped by 800uA, seems like good enough for you to use it.

[john.liu]

thank you for your support.