FreeRTOS Tick time modification

[sara]

I need to minimize current consumption when using FreeRTOS. I have merged freertos with the ble_app_uart example using SDK 15.3.0. I am getting the average current as 9.162 uA when FreeRTOS is configured with NRF_LOG_ENABLED set to 0. The FreeRTOS ticks I guess approx. at 1 sec. I want to reduce this 1 sec time to msec so what changes I need to do? I am testing on nrf5283 development board. I have attached two images: image uart_freertos_4.png showing time between the ticks which I want to change, and uart_freertos_3.png giving the average current consumption which I want to reduce it as close as 2-3 uA.

[Jared]

Hi,

Increasing the frequency of the FreeRTOS ticks will not minimize the current consumption. Have you done the steps mentioned in this guide?

regards

Jared 

[sara]

yes, Jared I have done the steps that are mentioned in the guide. I got the desired low current consumption when freeRTOS was not merged. But after adding freeRTOS I am not able to get the low current.

[eyalasko]

Hi @sara, 

I was banging my head for several weeks on a similar phenomena (in SDK 14.2)

Apparently, there is a shortcoming in freeRTOS power optimization.

See this post for details and workaround.

I Hope this helps.

Good luck.

[Август]

Thanks for your sharing.

I am still confused by a question.

When you open the log log task will be created and vApplicationIdleHook() will run and it's electric currents is 6ma.

Here is the setting

#define configUSE_IDLE_HOOK 1
#define NRF_LOG_ENABLED 1

#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
#endif // (NRFFOSDK-11174)
{
/* No SD - we would just block interrupts globally.
* BASEPRI cannot be used for that because it would prevent WFE from wake up.
*/
do{
__WFE();
} while (0 == (NVIC->ISPR[0] | NVIC->ISPR[1]));
}
}

void main(void)
{
log_init();
clock_init();
#if NRF_LOG_ENABLED
// Start execution.
if (pdPASS != xTaskCreate(logger_thread, "LOGGER", 256, NULL, 1, &m_logger_thread))
{
APP_ERROR_HANDLER(NRF_ERROR_NO_MEM);
}
#endif
// Activate deep sleep mode.
SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
ble_stack_init();
gap_params_init();
gatt_init();
advertising_init();
services_init();
conn_params_init();
nrf_sdh_freertos_init(NULL, NULL);
// advertising_start();
LogD("ble_init_ok\r\n");
// Start FreeRTOS scheduler.
vTaskStartScheduler();
for (;;)
{
APP_ERROR_HANDLER(NRF_ERROR_FORBIDDEN);
}

}