Application with FreeRTOS - lowest possible current in idle.

RE: Application with FreeRTOS - lowest possible current in idle.

grzegorz — Fri, 07 Dec 2018 23:28:20 GMT

With this modification I have much worse results. Current increased on my board from 1 mA to 7 mA. I think Nordic should really look into current consumption of FreeRTOS apps. Especially ble_app_hrs_freertos which is expected to be an example to follow. But now current consumption is quite high. A lot could be improved. I know that you have seen nRF52840, SDK 14.0.0 and tickless idle FreeRTOS - some suggestions topic. Someone did great job there. Current consumption dropped on my board from 1 mA to 100 uA. I hope Nordic does similar optimization of ble_app_hrs_freertos for nRF52832 and newest SDK. Does Nordic plan to release really power optimized FreeRTOS example?

RE: Application with FreeRTOS - lowest possible current in idle.

WestCoastDaz — Mon, 24 Sep 2018 15:57:21 GMT

schef The current consumption decrease you highlighted here was due to the UART not running since you disabled logging. By the SDK examples have UART based logging enabled by default and in my experience the UART consumes ~ 400uA.

RE: Application with FreeRTOS - lowest possible current in idle.

schef — Tue, 07 Aug 2018 12:41:59 GMT

I have investigated more i have found out that the solution by disabling NRF_LOG_ENABLED solved the current consumption issue. I was trying to find why log was consuming power by enabling NRF_LOG_ENABLED, set the NRF_LOG_DEFERRED to 0 and removing the m_logger_thread and it did decrease but then i got some HARDFAULT. I guess it was related by printing in the interrupt?

Here are the results with the NRFFOSDK-11174 set to 1 and NRF_LOG_ENABLED 0:

ble_app_hrs_freertos:
- with adv active: 150uA
- after adv timeout: 9uA

RE: Application with FreeRTOS - lowest possible current in idle.

schef — Mon, 06 Aug 2018 15:20:06 GMT

Hi guys i have tried the solution you have proposed with commenting out `#if 0` and the result is much worse on my custom nrf52832 board when advertising.

ble_app_hrs_freertos:

- Without modification:

- with adv active: 850uA

- after adv timeout: 8uA

- With modification:

- with adv active: 6mA

- after adv timeout: 8uA

ble_app_hrs:

- with adv active: 525uA

- after adv timeout: 8uA

ble_app_hrs (sdk_14.2):

- with adv active: 534uA

- after adv timeout: 8uA

my_custom_app (sdk_14.2):

- with adv active: 84uA

- without adv: 54uA

I'm not sure why my custom app consumes only 84uA and ble_app_hrs more and why the implementation with RTOS consumes double the without.

RE: Application with FreeRTOS - lowest possible current in idle.

Susheel Nuguru — Sun, 17 Jun 2018 18:57:38 GMT

Yes, sounds about right

RE: Application with FreeRTOS - lowest possible current in idle.

Al Bundy — Thu, 14 Jun 2018 14:22:51 GMT

Dear @Aryan,

I am using Rigol oscilloscope and uCurrent GOLD to measure the actual current consumption.

I have done your simple test and the result looks really promising. On the range of 1mV/uA I do not see any DC base. To do tests on 1mV/nA I need to do some application adjustments cause there will be 10k resistor in series with battery.

Can you confirm me that what I should measure in idle state is something about 2-3 uA?

RE: Application with FreeRTOS - lowest possible current in idle.

Susheel Nuguru — Thu, 14 Jun 2018 13:05:44 GMT

Hi,

Not sure how you are calculating the base current.

But can you do a simple idle test with the following change in SDK\external\freertos\portable\CMSIS\port_cmsis_systick.c file

//#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)

Notice that i have commented out now the #if 0 line. If you get better results, then i will remove them and check that in the SDK.