Power consumption using FreeRTOS

RE: Power consumption using FreeRTOS

shai.c — Thu, 11 Jun 2020 06:46:11 GMT

Hi Susheel,

Thanks for your answer, I tested it and the behavior looks like using WFE

RE: Power consumption using FreeRTOS

Susheel Nuguru — Wed, 10 Jun 2020 09:48:00 GMT

Hi Shai,

Verified your descritption. You were right. Something is causing the softdevice wakeup too early. Please replace the sd_app_evt_wait with the below code in port_cmsis_systick.c. I have verified my suggestion to improve the power. We will investigate further if this behaviour is same with the coming SD versions to see if we need to fix something.

        if ( xModifiableIdleTime > 0 )
        {
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
                do{
                  uint32_t err_code = sd_app_evt_wait();
                  APP_ERROR_CHECK(err_code);
                } while (0 == (NVIC->ISPR[0] | NVIC->ISPR[1]));
            }

RE: Power consumption using FreeRTOS

shai.c — Wed, 10 Jun 2020 08:44:48 GMT

Hi,

Attached hrs freertos_hrs project

devzone.nordicsemi.com/.../4810.ble_5F00_app_5F00_hrs_5F00_freertos.zip

RE: Power consumption using FreeRTOS

Susheel Nuguru — Wed, 10 Jun 2020 08:39:05 GMT

I am sorry for coming back late. I am struggling a bit trying to make the SDK16 SES freertos_hrs project run on pca10100.

Just changing the preprocessing defines
replacing startupfiles to match nrf52833
and fixing linker values seems not enough.

Can I please get your project that runs on pca10100 on sdk16, so that I flash and see the results in the power profiler.

RE: Power consumption using FreeRTOS

shai.c — Mon, 08 Jun 2020 10:39:07 GMT

Thanks for your answer, but disabling and then enabling the MWU didn't change the power consumption

I will be glad if you will test it

Thanks

RE: Power consumption using FreeRTOS

Susheel Nuguru — Mon, 08 Jun 2020 10:16:26 GMT

I am sorry, I realized that my new nRF52833 board did not have the SB bridge cut to make the power measurement.

In your latest reply you say that you see a significant improvement with WFE, then this is something we saw before

I suspect that this is because of the use of MWU inside of sd, that causes this spike as seen in this thread.

Try disabling the MWU before sd_app_event_wait and enabling just after wakeup in the port_cmsis_systick.c file like below

// replace sd_app_evt_wait with
/* MWU Disable */
NRF_MWU->REGIONENCLR
    = ((MWU_REGIONENCLR_RGN0WA_Clear << MWU_REGIONENCLR_RGN0WA_Pos) 
     | (MWU_REGIONENCLR_PRGN0WA_Clear << MWU_REGIONENCLR_PRGN0WA_Pos));

sd_app_evt_wait();

/* MWU Enable */
NRF_MWU->REGIONENSET
    = ((MWU_REGIONENSET_RGN0WA_Set << MWU_REGIONENSET_RGN0WA_Pos) 
     | (MWU_REGIONENSET_PRGN0WA_Set << MWU_REGIONENSET_PRGN0WA_Pos));

I have not tested this since myself, but if this did not work, then I can fix my board and try to dig a bit deeper into it tomorrow.

RE: Power consumption using FreeRTOS

shai.c — Mon, 08 Jun 2020 09:12:21 GMT

Hi Susheel Nuguru

I'm using nRF52833 DK running ble_app_hrs_freertos example.

1. when using the following code:

        if ( xModifiableIdleTime > 0 )
        {
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
#if (__FPU_USED == 1)
             __set_FPSCR(__get_FPSCR() & ~(0x0000009F)); 
             (void) __get_FPSCR();
             NVIC_ClearPendingIRQ(FPU_IRQn);
#endif  __FPU_USED
                uint32_t err_code = sd_app_evt_wait();
                APP_ERROR_CHECK(err_code);
            }
            else
#endif  // SOFTDEVICE_PRESENT
            {
                /* 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]));
            }
        }

the average power consumption is: 5.794mA

2. when using the following code (forcing to use WFE):

        if ( xModifiableIdleTime > 0 )
        {
#if 0
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
#if (__FPU_USED == 1)
             __set_FPSCR(__get_FPSCR() & ~(0x0000009F)); 
             (void) __get_FPSCR();
             NVIC_ClearPendingIRQ(FPU_IRQn);
#endif  __FPU_USED
                uint32_t err_code = sd_app_evt_wait();
                APP_ERROR_CHECK(err_code);
            }
            else
#endif  // SOFTDEVICE_PRESENT
#endif  // if 0
            {
                /* 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]));
            }
        }

the average power consumption is: 102uA

Which example did you test?

Thanks, Shai

RE: Power consumption using FreeRTOS

Susheel Nuguru — Mon, 08 Jun 2020 08:40:53 GMT

Hi Shai,

That seems to be a lot of current from a peripheral keeping the HFCLK ON. That is not normal and is not consistent with the testing I have done here on the examples.

Are you testing this on nRF52833 DK board or is it a custom board? Have you disabled all tasks in your application and let the idle task run only to see how much current the idle application consumes?

RE: Power consumption using FreeRTOS

shai.c — Mon, 08 Jun 2020 08:29:33 GMT

Hi Susheel Nuguru

Any suggestions?

RE: Power consumption using FreeRTOS

shai.c — Wed, 03 Jun 2020 14:38:19 GMT

Hi,

I checked ERRATA 87 - CPU: Unexpected wake from System ON Idle when using FPU, according to the Workaround the following code need to be added before calling WFE

#if (__FPU_USED == 1)
 _set_FPSCR(_get_FPSCR() & ~(0x0000009F)); 
 (void) __get_FPSCR();
 NVIC_ClearPendingIRQ(FPU_IRQn);
#endif

Does this code need to be added also before calling sd_app_evt_wait? ( I'm using SOFTDEVICE)

however, I tried to add this before calling sd_app_evt_wait but it didn't help

Any other suggestions?

RE: Power consumption using FreeRTOS

Susheel Nuguru — Wed, 03 Jun 2020 11:35:14 GMT

I cannot think of anything.very specific.

Please check if you are hit by ERRATA 78 or 87 as mentioned here