How does the device receive messages from the parent node when it goes into low power?

[liisa]

Hi, the nordic team

I am working on thread protocol using SDK version 2.9.1. 

I use the SED device,My poll is 1000 ms. How can I receive messages from my parent node when my SED device goes into low power?

Here is my code to get into low power:

 int main(void)
 {
        if (IS_ENABLED(CONFIG_RAM_POWER_DOWN_LIBRARY)) {
		power_down_unused_ram();
	}

        int err;

        k_timer_init(&led_timer, on_led_timer_expiry, on_led_timer_stop);
	k_timer_init(&provisioning_timer, on_provisioning_timer_expiry, NULL);

	k_work_queue_init(&coap_server_workq);
	k_work_queue_start(&coap_server_workq, coap_server_workq_stack_area,
					K_THREAD_STACK_SIZEOF(coap_server_workq_stack_area),
					COAP_SERVER_WORKQ_PRIORITY, NULL);
	k_work_init(&provisioning_work, activate_provisioning);

        if (IS_ENABLED(CONFIG_OPENTHREAD_MTD_SED)) {
		k_work_init(&poll_change_work,
                        into_low_power_sleeply);
	}

        err = ot_coap_init(&deactivate_provisionig, &on_light_request);
        if (err) {
		LOG_ERR("Could not initialize OpenThread CoAP");
		goto end;
	}
         
        err = dk_leds_init();
        if (err) {
                LOG_ERR("Cannot init LEDs (err: %d)", err);
                goto end;
        }

        err = dk_buttons_init(button_pressed_callback);
        if (err)
        {
                LOG_ERR("Cannot init buttons (err: %d)", err);
                goto end;
        }
        
            // 点亮 LED1
        dk_set_led_on(OT_CONNECTION_LED);
        err = restore_network_data();
end:
        return 0;
         
 }
 
 //改变poll时间,进入低功耗
static void into_low_power_sleeply(struct k_work *item)
{
        ARG_UNUSED(item);

        otError error;
	otLinkModeConfig mode;
	struct openthread_context *context = openthread_get_default_context();

	__ASSERT_NO_MSG(context != NULL);

	openthread_api_mutex_lock(context);
	mode = otThreadGetLinkMode(context->instance);
	mode.mRxOnWhenIdle = false;
	error = otThreadSetLinkMode(context->instance, mode);
        otLinkSetPollPeriod(context->instance, OT_POLL_PERIOD);
	openthread_api_mutex_unlock(context);

	if (error != OT_ERROR_NONE) {
		LOG_ERR("Failed to set MLE link mode configuration");
	}

#if IS_ENABLED(CONFIG_PM_DEVICE)
	const struct device *cons = DEVICE_DT_GET(DT_CHOSEN(zephyr_console));

	if (!device_is_ready(cons)) {
		return;
	}

        pm_device_action_run(cons, PM_DEVICE_ACTION_SUSPEND);
#endif

        dk_set_led_off(OT_CONNECTION_LED);
        dk_set_led_off(PROVISIONING_LED);
        dk_set_led_off(LIGHT_LED);
}