nRF52832 Timer power consumption

[shai.c]

Hi

I'm using nRF52832, SDK 16.

When I enabling timer application the power consumption is increased by ~450uA, far away from the product specification

const nrf_drv_timer_t TIMER_LED = NRF_DRV_TIMER_INSTANCE(0);

/**
 * @brief Handler for timer events.
 */
void timer_led_event_handler(nrf_timer_event_t event_type, void* p_context)
{

}


/**
 * @brief Function for main application entry.
 */
int main(void)
{
    uint32_t time_ms = 500; //Time(in miliseconds) between consecutive compare events.
    uint32_t time_ticks;
    uint32_t err_code = NRF_SUCCESS;


    //Configure TIMER_LED for generating simple light effect - leds on board will invert his state one after the other.
    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    err_code = nrf_drv_timer_init(&TIMER_LED, &timer_cfg, timer_led_event_handler);
    APP_ERROR_CHECK(err_code);

    time_ticks = nrf_drv_timer_ms_to_ticks(&TIMER_LED, time_ms);

    nrf_drv_timer_extended_compare(
         &TIMER_LED, NRF_TIMER_CC_CHANNEL0, time_ticks, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true);

    nrf_drv_timer_enable(&TIMER_LED);

    while (1)
    {
        __WFI();
    }
}

What may cause to this difference?

Thanks

[Simonr]

Hi

A current draw of ~450 µA pints to the HFCLK being kept running, which seems to be the case here. To minimize current consumption I would suggest looking at I.E. the RTC example project which uses the LF clock to keep track of time and will draw way less power than if the HF clock is being kept running.

Best regards,

Simon

[shai.c]

Hi Simon,

Which clock is using in Timer Example? isn't it LF clock?

[Simonr]

This is a link to the RTC example. Yes, this is using the LF clock, but I assume you're pointing to some other example? If it's the \examples\peripheral\timer you're referring to, this is by no means optimized for low current consumption. Please make sure that the HF clock is not initialized and started somewhere in your application.

Best regards,

Simon

[shai.c]

My mistake with the link, the correct one is: \examples\peripheral\timer Time Example

"Please make sure that the HF clock is not initialized and started somewhere in your application" - In this example, there is no use of HF Clock.

[Simonr]

Hi

The current consumption of the timer example is affected by what frequency you have set your timer to use. The datasheet only looks at the current consumption of the peripheral itself. When the 16MHz clock is enabled, there are a few other parts of the digital domain that also consume more power. This is unfortunately not documented that well.

Best regards,

Simon