nRF52840 is anything dependent on power management?

[BEplane]

Hello,

nRF52840-DK

SDK: 15.3.0

SoftDevice: s140

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fclock.html

Do any drivers, or libraries depend on power management? From the link above, the DFU is the only feature that needs the power management. We are trying to remove nrf_pwr_mgmt_run() from main, and determine if any unknown issues will arise. We are not currently observing any issues in small tests, but we also do not want to error, or halt during run time.

We plan on adding the BLE Buttonless DFU in the near future, but currently would like to confirm with or without power management, (more specifically calling nrf_pwr_mgmt_run in main) what will potentially cause issues. 

Thank you,

[Øyvind]

Hi BEplane,

From the link above, the DFU is the only feature that needs the power management

 Not sure what you are referring to. The link points to the clock chapter of nRF52832, with no mention of DFU.

We are trying to remove nrf_pwr_mgmt_run() from main, and determine if any unknown issues will arise

 What example are you running? All examples call nrf_pwr_mgmt_run() in idle_state_handle():

/**@brief Function for handling the idle state (main loop).
 *
 * @details Handles any pending log or key operations, or both, then sleeps until the next event occurs.
 */
static void idle_state_handle(void)
{
    ret_code_t err_code;
    
    err_code = nrf_ble_lesc_request_handler();
    APP_ERROR_CHECK(err_code);
    
    if (NRF_LOG_PROCESS() == false)
    {
        nrf_pwr_mgmt_run();
    }
}

void nrf_pwr_mgmt_run(void)
{
    PWR_MGMT_FPU_SLEEP_PREPARE();
    PWR_MGMT_SLEEP_LOCK_ACQUIRE();
    PWR_MGMT_CPU_USAGE_MONITOR_SECTION_ENTER();
    PWR_MGMT_DEBUG_PIN_SET();

    // Wait for an event.
#ifdef SOFTDEVICE_PRESENT
    if (nrf_sdh_is_enabled())
    {
        ret_code_t ret_code = sd_app_evt_wait();
        ASSERT((ret_code == NRF_SUCCESS) || (ret_code == NRF_ERROR_SOFTDEVICE_NOT_ENABLED));
        UNUSED_VARIABLE(ret_code);
    }
    else
#endif // SOFTDEVICE_PRESENT
    {
        // Wait for an event.
        __WFE();
        // Clear the internal event register.
        __SEV();
        __WFE();
    }

    PWR_MGMT_DEBUG_PIN_CLEAR();
    PWR_MGMT_CPU_USAGE_MONITOR_SECTION_EXIT();
    PWR_MGMT_SLEEP_LOCK_RELEASE();
}

The DFU service (components\ble\ble_services\ble_dfu\ble_dfu.h), however, calls 

nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_DFU);

/**@brief Function for shutting down the system.
 *
 * @param[in] shutdown_type     Type of operation.
 *
 * @details All callbacks will be executed prior to shutdown.
 */
void nrf_pwr_mgmt_shutdown(nrf_pwr_mgmt_shutdown_t shutdown_type);

I suggest having a look at the Power Management library (components\libraries\pwr_mgmt\nrf_pwr_mgmt.h) 

[BEplane]

Sorry I copied from the main browser URL, not the Copy URL button, so it went to the previous page I was viewing. I was referring to the power management

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/lib_pwr_mgmt.html

Yes that is is function that is being called. I am inquiring if leaving the power management setup, but removing that call (nrf_pwr_mgmt_run) will have any negative effect of properly running other features provided by Nordic.

This is a broad question, but the power management is baked into most examples, so I would like to better understand any unseen complications for removing only the call (nrf_pwr_mgmt_run) from a project.

My expectation is that all other features will work, and the processor will not go to sleep. Causing a small increase in power consumption.

[Øyvind]

BEplane said:

My expectation is that all other features will work, and the processor will not go to sleep. Causing a small increase in power consumption.

 Yes, that is correct. Removing the nrf_pwr_mgmt_run(), not the idle_state_handle(), will only prevent device from sleeping (power saving).