ble app uart

[nicky_liu]

Hi：

I use nrf52832 to connect to the sensor module through uart. When the sensor device is turned off, I can repeat the pairing and unpairing of the Ble module through the nRF Connect app. But after the Ble module pairing is completed and the sensor is turned on, when I cancel the Ble pairing and want to re-pair, I cannot scan the Ble device and cannot pair. How can I solve it

[Karl Ylvisaker]

Hello,

If the device does not show up again in the nRF Connect application scanner after a disconnect it is likely due to the device not advertising. 
Could you make sure that your device restarts advertising when a connection is disconnected?

Do I understand you correctly that you are working with the BLE UART example? If so, have you made any modifications to the example application?

Best regards,
Karl

[nicky_liu]

Yes, I am using the ble_app_uart example. For the example, I only modify MIN_CONN_INTERVAL and MAX_CONN_INTERVAL.

This problem only occurs when the sensor device is turned on, how can I modify it for the ble example?

[nicky_liu]

Thank you for your reply, but I can't find pm_evt_handler() in the ble app uart example. Is it set by ble_evt_handler (SDK 17.0.2)? Is there any relevant example?

[Karl Ylvisaker]

nicky_liu said:

Thank you for your reply

No problem at all, I am happy to help!

nicky_liu said:

Is there any relevant example?

You will need to add the peer manager to your application if you intend to support pairing, re-pairing and/or bonding. By default the ble_app_uart does not actually use any encryption / security as it is mainly meant as a demonstration of how to set up the most generic custom service.
There is indeed a couple of examples demonstrating the use of the peer manager, such as the Blood pressure example and heart rate example - both of which require a higher security level for their services.
You can also read more about the peer manager in general in its library documentation.

Please do not hesitate to ask if any part of this still should be unclear, or if you have any other questions about this!

Best regards,
Karl

[nicky_liu]

Hi Karl：

  I am trying to modify the project file, but there seems to be some problems with the header, how can I solve it?

[Karl Ylvisaker]

Hello,

It seems like you have not enabled the peer manager module in your sdk_config.
Please check the sdk_config of the ble hrs example to see how this could be done.

Best regards,
Karl

[nicky_liu]

I modified the code according to your suggestion, but the problem still exists. Can you check the modified part for me?

/**@brief Function for handling Peer Manager events.
 *
 * @param[in] p_evt  Peer Manager event.
 */
static void pm_evt_handler(pm_evt_t const * p_evt)
{
    ret_code_t err_code;
    bool       is_indication_enabled;

    pm_handler_on_pm_evt(p_evt);
    pm_handler_flash_clean(p_evt);

    switch (p_evt->evt_id)
    {
        case PM_EVT_CONN_SEC_CONFIG_REQ:
        {
            // Allow or reject pairing request from an already bonded peer.
            pm_conn_sec_config_t conn_sec_config = {.allow_repairing = true};
            pm_conn_sec_config_reply(p_evt->conn_handle, &conn_sec_config);
        }
            break;

        case PM_EVT_PEERS_DELETE_SUCCEEDED:
        {
            advertising_start();
        }
            break;

        default:
            break;
    }
}


/**@brief Function for the Peer Manager initialization.
 */
static void peer_manager_init(void)
{
    ble_gap_sec_params_t sec_param;
    ret_code_t           err_code;

    err_code = pm_init();
    APP_ERROR_CHECK(err_code);

    memset(&sec_param, 0, sizeof(ble_gap_sec_params_t));

    // Security parameters to be used for all security procedures.
    sec_param.bond           = SEC_PARAM_BOND;
    sec_param.mitm           = SEC_PARAM_MITM;
    sec_param.lesc           = SEC_PARAM_LESC;
    sec_param.keypress       = SEC_PARAM_KEYPRESS;
    sec_param.io_caps        = SEC_PARAM_IO_CAPABILITIES;
    sec_param.oob            = SEC_PARAM_OOB;
    sec_param.min_key_size   = SEC_PARAM_MIN_KEY_SIZE;
    sec_param.max_key_size   = SEC_PARAM_MAX_KEY_SIZE;
    sec_param.kdist_own.enc  = 1;
    sec_param.kdist_own.id   = 1;
    sec_param.kdist_peer.enc = 1;
    sec_param.kdist_peer.id  = 1;

    err_code = pm_sec_params_set(&sec_param);
    APP_ERROR_CHECK(err_code);

    err_code = pm_register(pm_evt_handler);
    APP_ERROR_CHECK(err_code);
}



/**@brief Application main function.
 */
int main(void)
{
    bool erase_bonds;

    // Initialize.
    uart_init();
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();
    peer_manager_init();

    // Start execution.
    printf("\r\nUART started.\r\n");
    NRF_LOG_INFO("Debug logging for UART over RTT started.");
    advertising_start();

    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}


/**
 * @}
 */

[Karl Ylvisaker]

Hello,

Could you confirm for me that you have defined PEER_MANAGER_ENABLED 1 in your sdk_config.h file? Every driver or module that is not enabled in the sdk_config will be excluded from compilation.

Best regards,
Karl

[nicky_liu]

Sorry, I didn't express it clearly. After modifying sdk_config.h according to your suggestion, the program can work, but the device still cannot be re-paired. Can you help me confirm the modified part of the main.c file?

[Karl Ylvisaker]

Aha, now I understand - I was under the impression that you were still talking about the sdk_config issue.

I do not immediately see anything wrong with this event handler, no.
Could you place a breakpoint in the PM_EVT_CONN_CONFIG_REQ  section, to confirm that you receive this event when a new connection is made?
Are you able to pair, but not re-pair?
Which error are you getting when you attempt to re-pair?
What does you log say when this happens?

Best regards,
Karl

[nicky_liu]

Hi Karl:

The following is the message I received from debug Treminal. It seems to be caused by APP_UART_COMMUNICATION_ERROR in main.c

[nicky_liu]

Sorry, the wrong code should be in the red box below