What happens When nRF52832 awakes from sleep mode ?

[enkavak]

Hello,

        I'm usign nRF52832 with nRF5_SDK v15. I'm using "ble_app_uart" example. I just wanted to know that What is the wake up procedure of the MCU when we call the sleep function below ?

        sleep_mode_enter();

        Is the MCU awakes where it was sleep or it awakes from the beginning of the code ?

        does it re-initialize the BLE hardware every time it wakes up ?

Best Regards

[bjorn-spockeli]

If you take a look at the function definition, attached below, you'll see that sd_power_system_off() is called, i.e. the chip sent to System OFF and waking up the chip will result in a reset( as mentioned in the comments)

static void sleep_mode_enter(void)
{
    uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    // Prepare wakeup buttons.
    err_code = bsp_btn_ble_sleep_mode_prepare();
    APP_ERROR_CHECK(err_code);

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);
}

If you the chip to go to System ON: Low Power mode, then you can call nrf_pwr_mgmt_run() , which in turn calls sd_app_evt_wait().  This will put the chip in a low power state where it waits for interrupts from the SoftDevice and/or peripherals, i.e. code execution continues from where sd_app_evt_wait was called.