LTE handler deregistered

Hi!

I am experiencing some odd behavior from the modem, and I hope you can help me understand it:

After I disconnect from LTE using lte_lc_func_mode_set(LTE_LC_FUNC_MODE_DEACTIVATE_LTE), the lte_handler somehow get de-registered. When I try to turn LTE on later, I get notifications from the GNSS handler that it sometimes get blocked, but I get nothing from the LTE handler.

When the NRF_MODEM_GNSS_EVT_PERIODIC_WAKEUP event gets called, I submit a thread to reconnect to LTE.

I have tried activating LTE with several different methods, both lte_lc_func_mode_set(LTE_LC_FUNC_MODE_ACTIVATE_LTE), lte_lc_connect_async(lte_handler) and lte_lc_init_and_connect_async(lte_handler), but they all give the same result (Also tried with NULL argument, as the handler already is registered).

I've even tried calling the full modem_init routine (as seen in different samples, including MAGPIO/COEX0 config, lte_lc_init, lte_lc_psm_req, lte_lc_connect_async(lte_handler)). The LTE handler does not react, and the thread is locked waiting for a semaphore that should be set in a LTE handler event.

Do you have any suggestions as to how I can get the LTE handler back up?

Thank you for all your help!

Kind regards,

Torje

0 Albrecht Markus Schellenberger over 4 years ago

Hei Torje,

Do you have any suggestions as to how I can get the LTE handler back up?

Trying to reproduce the basic concept of your approach, I did not manage to succeed. I took the Hello World sample as a reference and added the following lines of code:

main.c

/*
 * Copyright (c) 2012-2014 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr.h>
#include <modem/lte_lc.h>

/* Semaphore used to block the main thread until the link controller has
 * established an LTE connection.
 */
K_SEM_DEFINE(lte_connected, 0, 1);
K_SEM_DEFINE(enter_psm, 0, 1);
K_SEM_DEFINE(disable_lte, 0, 1);

static void lte_handler(const struct lte_lc_evt *const evt)
{
     switch (evt->type) {
     case LTE_LC_EVT_NW_REG_STATUS:
		if ((evt->nw_reg_status != LTE_LC_NW_REG_REGISTERED_HOME) &&
		(evt->nw_reg_status != LTE_LC_NW_REG_REGISTERED_ROAMING)) {
		
			if(evt->nw_reg_status == LTE_LC_NW_REG_NOT_REGISTERED) {
				printk("Network connection lost!\n");
				k_sem_give(&disable_lte);
			}
			break;
		}

		printk("Connected to: %s network\n",
		evt->nw_reg_status == LTE_LC_NW_REG_REGISTERED_HOME ? "home" : "roaming");

		k_sem_give(&lte_connected);

		break;
     case LTE_LC_EVT_PSM_UPDATE:
		printk("Power Saving Mode negotiation completed!\nTracking Area Update interval: %ds, Active Time: %ds\n", evt->psm_cfg.tau, evt->psm_cfg.active_time);
		break;
    case LTE_LC_EVT_MODEM_SLEEP_ENTER:
		if(evt->modem_sleep.type == LTE_LC_MODEM_SLEEP_PSM) {
			printk("Entering PSM. Good night!\n");
			k_sem_give(&enter_psm);
		}

		break;
	 case LTE_LC_EVT_EDRX_UPDATE:
     case LTE_LC_EVT_RRC_UPDATE:
     case LTE_LC_EVT_CELL_UPDATE:
     case LTE_LC_EVT_LTE_MODE_UPDATE:
     case LTE_LC_EVT_TAU_PRE_WARNING:
     case LTE_LC_EVT_NEIGHBOR_CELL_MEAS:
     case LTE_LC_EVT_MODEM_SLEEP_EXIT_PRE_WARNING:
     case LTE_LC_EVT_MODEM_SLEEP_EXIT:
             /* Callback events carrying LTE link data */
             break;
     default:
             break;
     }
}

void main(void)
{
	int err;
	enum lte_lc_func_mode func_mode;
	enum lte_lc_system_mode sys_mode;
	enum lte_lc_system_mode_preference sys_pref_mode;

	printk("Hello World! %s\n", CONFIG_BOARD);

	printk("Connecting to LTE network. This may take a few minutes...\n");

    err = lte_lc_init_and_connect_async(lte_handler);
    if (err) {
        printk("lte_lc_init_and_connect_async, error: %d\n", err);
        return;
    }

    k_sem_take(&lte_connected, K_FOREVER);

	/* Check current system & functional modes */
	err = lte_lc_system_mode_get(&sys_mode, &sys_pref_mode);
	if(err) {
		printk("Could not get modem system mode, error: %d\n", err);
		return;
	}
	else {
		printk("Current modem system mode: %d\n", sys_mode);
		printk("Current modem preferred system mode: %d\n", sys_pref_mode);
	}		
	
	err = lte_lc_func_mode_get(&func_mode);
	if(err) {
		printk("Could not get modem functional mode, error: %d\n", err);
		return;
	}
	else {
		printk("Current modem functional mode: %d\n", func_mode);
	}

	k_sem_take(&enter_psm, K_FOREVER);
	printk("Waiting for 10s...\n");
	k_msleep(10000);

	/* Continue execution... */

	/* Deactivate LTE services & cross-check new functional mode*/
	err = lte_lc_func_mode_set(LTE_LC_FUNC_MODE_DEACTIVATE_LTE);
	if(err) {
		printk("Could not set modem functional mode, error: %d\n", err);
		return;
	}
	err = lte_lc_func_mode_get(&func_mode);
	if(err) {
		printk("Could not get modem functional mode, error: %d\n", err);
		return;
	}
	else {
		printk("Current modem functional mode: %d\n", func_mode);
	}	

	k_sem_take(&disable_lte, K_FOREVER);
	printk("Waiting for 10s...\n");
	k_msleep(10000);

	/* Re-activate LTE services & cross-check new functional mode*/
	err = lte_lc_func_mode_set(LTE_LC_FUNC_MODE_ACTIVATE_LTE);
	if(err) {
		printk("Could not set modem functional mode, error: %d\n", err);
		return;
	}
	err = lte_lc_func_mode_get(&func_mode);
	if(err) {
		printk("Could not get modem functional mode, error: %d\n", err);
		return;
	}
	else {
		printk("Current modem functional mode: %d\n", func_mode);
	}	

	while(1);	
}

prj.conf

# LTE link control
CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_AUTO_INIT_AND_CONNECT=n
CONFIG_LTE_NETWORK_MODE_LTE_M_GPS=y
## Power saving timers.
### 320 hours PSM.
CONFIG_LTE_PSM_REQ_RPTAU="11000001"
### 20 seconds active time.
CONFIG_LTE_PSM_REQ_RAT="00001010"
## Enable notifications when modem enters PSM
CONFIG_LTE_LC_MODEM_SLEEP_NOTIFICATIONS=y

The output is as expected:

*** Booting Zephyr OS build v3.0.99-ncs1  ***
Hello World! nrf9160dk_nrf9160
Connecting to LTE network. This may take a few minutes...
Connected to: home network
Power Saving Mode negotiation completed!
Tracking Area Update interval: 1152000s, Active Time: 20s
Current modem system mode: 4
Current modem preferred system mode: 0
Current modem functional mode: 1
Entering PSM. Good night!
Waiting for 10s...
Network connection lost!
Current modem functional mode: 31
Waiting for 10s...
Current modem functional mode: 1
Connected to: home network
Entering PSM. Good night!

I probably need more input since I might not have added all the functionality you are using.

Venleg helsing,

Markus