conn_mgr and LTE-M PSM

[thijsfranssen]

Hi, 

I really like the new Zephyr conn_mgr, it is really easy to use, almost UNIX like. I am wondering what is now the best way to control PSM. Will CONFIG_LTE_LINK_CONTROL and lte_lc_connect_async interfere with the conn_mgr? Should I only use one of the options or can they exist next to each other? 

will CONN_MGR_IF_NO_AUTO_CONNECT and then connection using lte_lc work reliable?

I am searching for the "right" way to do. 

Thanks!

[Michal]

Hello,

I will have to look more into conn_mgr, but I am not sure if our LTE code is well-integrated with that feature.

To be safe I would recommend using our LTE link control library.

Best regards,

Michal

[thijsfranssen]

I can't get it to work on  SDK 2.5.0, it should be really straight forward, right? I took the example from the library page

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

/* Semaphore used to block the main thread until modem has established
 * an LTE connection.
 */
K_SEM_DEFINE(lte_connected, 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) {
                        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:
        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:
        case LTE_LC_EVT_MODEM_SLEEP_ENTER:
        case LTE_LC_EVT_MODEM_EVENT:
                /* Handle LTE events */
                break;

        default:
                break;
        }
}

int main(void)
{
        int err;

        printk("Connecting to LTE network. This may take a few minutes...\n");
        err = lte_lc_init_and_connect_async(lte_handler);
        if (err) {
                printk("Failed to connect to LTE network, err %d\n", err);
                return err;
        }

        k_sem_take(&lte_connected, K_FOREVER);

}

I get 

Failed to connect to LTE network, err -14

I am just looking for an example with SDK 2.5.0 and PSM. Most samples like the AWS IOT example switched to the conn_mgr implementation.