`nrf_pwr_mgmt_run` returns immediately, and the return value is 0.

[Jack.Hong]

I used nRF52840 with nRF5 SDK 17.1.0

Also use freeRTOS from example "ble_app_hrs_freertos"

I need implement System-On mode deepsleep mode.
So I use nrf_pwr_mgmt_run API in my main task.

bool System_Sleep(void)
{
Log("%s: +", __func__);

uint32_t ret = 0;

Log("%s: enter real sleep", __func__);

stopSleepTimer();

vTaskSuspendAll();

//taskDISABLE_INTERRUPTS(); // if enable this, will block in nrf_pwr_mgmt_run and then does not wakeup by everthing.

RegisterWakeupSource();

{
nrf_pwr_mgmt_run();
//ret = sd_app_evt_wait();

sd_evt_get(&ret);
}
UnregisterWakeupSource();

taskENABLE_INTERRUPTS();

xTaskResumeAll();

resetSleepTimer();

Log("%s: ret %d -", __func__, ret);
return true;
}

But "nrf_pwr_mgmt_run" API will return immediately,

sd_evt_get value is '0'.

how to enter deepsleep mode with System On mode?

[Susheel Nuguru]

FreeRTOS provides vApplicationIdleHook to give you safe time to go to low power modes? You can call nrf_pwr_mgmt_run in that instead.

Or as mentioned in this just before calling nrf_pwr_mgmt_run, for debug reasons, print to see any pending IRQs keeping the system awake.

for (int i = 0; i < 32; i++) {
    if (NVIC_GetPendingIRQ(i)) {
        printk("IRQ %d is pending\n", i);
    }
}