power consumption is too high on my nrf52 SoC

RE: power consumption is too high on my nrf52 SoC

Juliusc — Thu, 23 Nov 2023 08:30:22 GMT

alright, thanks so much for your help you provided very valuable input!

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Thu, 23 Nov 2023 07:43:37 GMT

You need to change the way you trigger SAADC sampling if you want to reduce the sleep current. The typ. system current with a TIMER instance running in System ON is around 500 uA (see TIMER running). I would recommend just using the app timer and trigger sampling from a timer callback.

RE: power consumption is too high on my nrf52 SoC

Juliusc — Wed, 22 Nov 2023 15:07:13 GMT

what do I need to do in this function to decrease the power consumption:

void saadc_sampling_event_init(void)
{
    ret_code_t err_code;

    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, timer_handler);
    APP_ERROR_CHECK(err_code);

    /* setup m_timer for compare event every 400ms */
    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 400);
    nrf_drv_timer_extended_compare(&m_timer,
                                   NRF_TIMER_CC_CHANNEL0,
                                   ticks,
                                   NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
                                   false);
    nrf_drv_timer_enable(&m_timer);

    uint32_t timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&m_timer,
                                                                                NRF_TIMER_CC_CHANNEL0);
    uint32_t saadc_sample_task_addr   = nrf_drv_saadc_sample_task_get();

    /* setup ppi channel so that timer compare event is triggering sample task in SAADC */
    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel,
                                          timer_compare_event_addr,
                                          saadc_sample_task_addr);
    APP_ERROR_CHECK(err_code);
}

RE: power consumption is too high on my nrf52 SoC

Juliusc — Wed, 22 Nov 2023 14:46:19 GMT

ok thanks so I will leave this out and I also found out that my saadc sampling is responsible for most of the drainage besides that.

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Wed, 22 Nov 2023 10:47:35 GMT

Writing '1' to NRF_CLOCK->TASKS_HFCLKSTART will start the 32 MHz crystal oscillator, and the crystal oscillator is not automatically released in sleep. The run current with the oscillator active is about 200 uA.

RE: power consumption is too high on my nrf52 SoC

Juliusc — Wed, 22 Nov 2023 10:31:18 GMT

still it looks like something is requesting air time every ms, the advertising event only occurs every 500ms as defined, thats whats so weird

RE: power consumption is too high on my nrf52 SoC

Juliusc — Wed, 22 Nov 2023 09:44:13 GMT

I actually noticed something while investigating, I used the following lines in my ble setup:

  NRF_CLOCK->TASKS_HFCLKSTART  = 1;
  while ( NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);

and when commenting them , the average went down significantly (at least on the DK, I will test this on my custom PCB later). Though I think I included this because there was a problem with the SD but I cannot pinpoint what exactly it was. What are your thoughts on this?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Wed, 22 Nov 2023 08:50:01 GMT

if i run it on the DK with only the WFE main loop it takes 20uA

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Tue, 21 Nov 2023 10:23:16 GMT

The idle current would not have dropped below the CPU run current if the system did not enter sleep. The CPU run current ranges from approximately 2.8 mA to 6.3 mA depending on the supply and regulator configuration. There might be something that is either requesting system resources, such as the 16 MHz clock in sleep mode, or causing leakage from the IOs.

Do you measure a different sleep current if you comment out everything except the main loop in your main() function while running on the DK?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 15:06:20 GMT

I could try to trim it down, its basically only the ble file then anyways, I could send you the params Im using without the services

how do I know if WFE() actually works? I got the feeling it doesnt really shut down the uC.

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 14:46:45 GMT

You still have a high idle current, although it's much less noisy. Either way, I need to know what your code is doing to understand what's causing this.

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 14:43:15 GMT

this is what I get running the exact same code on a PCA10056 DK

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 14:32:11 GMT

There wasn't much to see in that function. Do you have a DK you can try this on? Alternatively, could you share your whole project here or in a private ticket so I can try it here?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 14:29:07 GMT

int main(void) {

  gpio_init();

  ble_init();

  flash_init();

  ble_advertise();

  while (1) {
     __WFE();
  }

}

gpio_init as I said just initializes (clears) some pins, ble_init() does the usual initialization of services etc, in flash init I just read from flash so no further interefering processes from there, I also have no scheduler enabled. I also tried sd_app_evt_wait() but no difference here

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 14:25:28 GMT

Are you able to share your main() function here?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 14:23:28 GMT

yeah exactly thats why i made this thread I never see like near 0 current or 'real' sleeping intervals its just always like this, my advertising interval is around 300ms

the event where my arrow is pointing is supposed to be the advertising I think:

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 14:19:54 GMT

You should be able to see the sleep/floor current between advertising events (assuming the spikes are BLE events and not some other noise).

Do you start an advertiser after you enable BLE? In that case, what interval are you advertising at?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 14:08:46 GMT

yes, its 450uA on average if I turn on BLE (as seen in the image provided)

without BLE its 220 on average but as I said I want to focus on the BLE problem first.

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 14:02:00 GMT

You can also see leakage from IOs in System OFF as the GPIO peripheral configurations are retained in OFF mode. Is possible to cut the power to the radar IC, or is it powered with the nRF?

[quote user="Juliusc"]and thats the current I see then. this still doesnt explain the residual 200uA when using BLE[/quote]

Not sure I understand the relation with BLE. Does the floor current increase when you enable BLE?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 13:24:19 GMT

yeah some leakage comes from there, like around 220uA, I know this, since I also used a fw that just says NRF_POWER->SYSTEMOFF = 1; and thats the current I see then. this still doesnt explain the residual 200uA when using BLE

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 13:15:30 GMT

Is the radar chip powered from the power rail as the nRF5, and is it possible that you may say current leakage from this IC if the nRF5 is no driving the pins to a defined state?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 13:05:29 GMT

yes I have a radar chip connected to those pins, though this isnt really the problem that I see with my power. Or do you think theres more to that?

One of the pins is connected with a not-gate maybe this is the reason why some current was drawn through that.

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 13:03:22 GMT

Thanks for confirming. Did you check what pin configuration of those pins were first? Also, are these pins connected to anything on your board?

RE: power consumption is too high on my nrf52 SoC

Juliusc — Mon, 20 Nov 2023 13:00:28 GMT

nRF5 SDK

I see I noticed that the current is a bit higher when I dont set certain gpio pins to clear specifically.

RE: power consumption is too high on my nrf52 SoC

Vidar Berg — Mon, 20 Nov 2023 12:58:43 GMT

Hi Julius,

Unused pins can be left floating without affecting the sleep current as GPIO pins are configured as inputs with the input buffer disconnect after reset.

Are you developing with the nRF Connect SDK or the nRF5 SDK?

Best regards,

Vidar