Connection parameters in nrf ble

want to know how can i judge that the variation is caused in the connection interval, connection supervision timeout, slave latency once i have flashed ble_app_template code in nrf52832 s132.

Parents Reply
  • The central decides the connection interval (and all the other connection parameters), but the peripheral might request certain changes, or reject the connection parameters the central decides (rejecting the parameters means that the peripheral will terminate the connection).

    You can set the connection interval by changing the NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL and NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL in sdk_config.
    You may set them to the same value, to force a specific connection interval.

    Best regards,
    Karl

Children
  • this NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL  you have told for central code??

    if want want to set the Connection Interval as 100ms in peripheral,  how will i set it? i know that this

     #define MIN_CONN_INTERVAL               MSEC_TO_UNITS(20, UNIT_1_25_MS) and 

    #define MAX_CONN_INTERVAL               MSEC_TO_UNITS(75, UNIT_1_25_MS)       commands are used but how to set value of Connection Interval as 100ms using these?? 

  • Ridhi said:
    this NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL  you have told for central code??

    Yes, these defines are used on the central side.
    The equivalent defines for the peripheral side are the ones you mention, MIN_CONN_INTERVAL and MAX_CONN_INTERVAL.
    If you want to set exactly 100 ms as the interval you must set both of these to 100 ms, like so:

    #define MIN_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)
    
    #define MAX_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)


    But keep in mind that the central has the final word, and may not always listen to the requests of the peripheral.

    Best regards,
    Karl

  • KARL, pls administer my queries

    1). if i want to set Connection interval as 1000ms say then, is this i will have to do:

    #define MIN_CONN_INTERVAL MSEC_TO_UNITS(1000, UNIT_1_25_MS)

    #define MAX_CONN_INTERVAL MSEC_TO_UNITS(1000, UNIT_1_25_MS) ?

    2). I have nrf connect app for android, ran nordic blinky code of nrf sdk v17.2 on nrf52832 dk. i checked this on power profiler kit 11. that as i clik on connect option in nrf app power profiler gives abou 50 ms delay between connection events and then later after 20ms then first connection parameters get changed and then it shows about 200ms CI. is this right i am understanding that master has intially set the CI as 50ms and then based on peripheral this interval was updated

  • Ridhi said:
    if i want to set Connection interval as 1000ms say then, is this i will have to do:

    Yes, this will set the peripheral's preferred connection interval to 1000 ms.
    But, since the peripheral does not decide the connection parameters it can only make a connection parameter update request with its preferred connection interval, and hope that the central will accept it.

    Ridhi said:
    I have nrf connect app for android, ran nordic blinky code of nrf sdk v17.2 on nrf52832 dk. i checked this on power profiler kit 11. that as i clik on connect option in nrf app power profiler gives abou 50 ms delay between connection events and then later after 20ms then first connection parameters get changed and then it shows about 200ms CI. is this right i am understanding that master has intially set the CI as 50ms and then based on peripheral this interval was updated

    You are right that the central has set whatever connection interval is being used.
    I can not say anything for certain about exactly which connection parameters are being used, since I have not seen a sniffer trace or logs of this, but it sounds like it could be the case that the central updated the connection interval after a request from the peripheral.
    Most of our BLE Peripheral examples will do a connection parameter update request after a timeout expires (usually 5 seconds), when it will ask to have the connection parameters updated to match its preferences. If you have not implemented this connection parameter update request in your own application yet I recommend that you take a look to see how it is done in the examples.

    If you are connecting to your peripherals using the nRF Connect application, could you share the log from a connected session? The logs will let us know what connection parameters are being used, and if it was updated by the central based on a request from the peripheral.

    Best regards,
    Karl

  • yes karl, to whatever code i use say ble _app_tempate as soon as click on connect button on nrf connect app on mobile it shows a CI of about 50ms and then when my timeout expires say 1second then the connection parameters are updated to what ever value i preffred. 

    Query: how initially this 50ms Connection Interval it is taking? i found the same in nordic bliky code also. Is that this duration  is set by nrf connect and later that when peripheral sends request fro update of connection parametres it takes those values which i have set ie 500ms

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     */
    /** @file
     *
     * @defgroup ble_sdk_app_template_main main.c
     * @{
     * @ingroup ble_sdk_app_template
     * @brief Template project main file.
     *
     * This file contains a template for creating a new application. It has the code necessary to wakeup
     * from button, advertise, get a connection restart advertising on disconnect and if no new
     * connection created go back to system-off mode.
     * It can easily be used as a starting point for creating a new application, the comments identified
     * with 'YOUR_JOB' indicates where and how you can customize.
     */
    
    #include <stdbool.h>
    #include <stdint.h>
    #include <string.h>
    
    #include "nordic_common.h"
    #include "nrf.h"
    #include "app_error.h"
    #include "ble.h"
    #include "ble_hci.h"
    #include "ble_srv_common.h"
    #include "ble_advdata.h"
    #include "ble_advertising.h"
    #include "ble_conn_params.h"
    #include "nrf_sdh.h"
    #include "nrf_sdh_soc.h"
    #include "nrf_sdh_ble.h"
    #include "app_timer.h"
    #include "fds.h"
    #include "peer_manager.h"
    #include "peer_manager_handler.h"
    #include "bsp_btn_ble.h"
    #include "sensorsim.h"
    #include "ble_conn_state.h"
    #include "nrf_ble_gatt.h"
    #include "nrf_ble_qwr.h"
    #include "nrf_pwr_mgmt.h"
    
    #include "nrf_log.h"
    #include "nrf_log_ctrl.h"
    #include "nrf_log_default_backends.h"
    
    
    #define DEVICE_NAME                     "Nordic_Template"                       /**< Name of device. Will be included in the advertising data. */
    #define MANUFACTURER_NAME               "NordicSemiconductor"                   /**< Manufacturer. Will be passed to Device Information Service. */
    #define APP_ADV_INTERVAL                MSEC_TO_UNITS(1000, UNIT_0_625_MS)                                    /**< The advertising interval (in units of 0.625 ms. This value corresponds to 187.5 ms). */
    
    #define APP_ADV_DURATION                18000                                   /**< The advertising duration (180 seconds) in units of 10 milliseconds. */
    #define APP_BLE_OBSERVER_PRIO           3                                       /**< Application's BLE observer priority. You shouldn't need to modify this value. */
    #define APP_BLE_CONN_CFG_TAG            1                                       /**< A tag identifying the SoftDevice BLE configuration. */
    
    #define MIN_CONN_INTERVAL              MSEC_TO_UNITS(500, UNIT_1_25_MS)        /**< Minimum acceptable connection interval (0.1 seconds). */
    #define MAX_CONN_INTERVAL              MSEC_TO_UNITS(500, UNIT_1_25_MS)       /**< Maximum acceptable connection interval (0.2 second). */
    #define SLAVE_LATENCY                   0                                       /**< Slave latency. */
    #define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(10000, UNIT_10_MS)         /**< Connection supervisory timeout (4 seconds). */
    
    #define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(1000)                   /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
    #define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                  /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
    #define MAX_CONN_PARAMS_UPDATE_COUNT    3                                       /**< Number of attempts before giving up the connection parameter negotiation. */
    
    #define SEC_PARAM_BOND                  1                                       /**< Perform bonding. */
    #define SEC_PARAM_MITM                  0                                       /**< Man In The Middle protection not required. */
    #define SEC_PARAM_LESC                  0                                       /**< LE Secure Connections not enabled. */
    #define SEC_PARAM_KEYPRESS              0                                       /**< Keypress notifications not enabled. */
    #define SEC_PARAM_IO_CAPABILITIES       BLE_GAP_IO_CAPS_NONE                    /**< No I/O capabilities. */
    #define SEC_PARAM_OOB                   0                                       /**< Out Of Band data not available. */
    #define SEC_PARAM_MIN_KEY_SIZE          7                                       /**< Minimum encryption key size. */
    #define SEC_PARAM_MAX_KEY_SIZE          16                                      /**< Maximum encryption key size. */
    
    #define DEAD_BEEF                       0xDEADBEEF                              /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */
    
    
    NRF_BLE_GATT_DEF(m_gatt);                                                       /**< GATT module instance. */
    NRF_BLE_QWR_DEF(m_qwr);                                                         /**< Context for the Queued Write module.*/
    BLE_ADVERTISING_DEF(m_advertising);                                             /**< Advertising module instance. */
    
    static uint16_t m_conn_handle = BLE_CONN_HANDLE_INVALID;                        /**< Handle of the current connection. */
    
    /* YOUR_JOB: Declare all services structure your application is using
     *  BLE_XYZ_DEF(m_xyz);
     */
    
    // YOUR_JOB: Use UUIDs for service(s) used in your application.
    static ble_uuid_t m_adv_uuids[] =                                               /**< Universally unique service identifiers. */
    {
        {BLE_UUID_DEVICE_INFORMATION_SERVICE, BLE_UUID_TYPE_BLE}
    };
    
    
    static void advertising_start(bool erase_bonds);
    
    
    /**@brief Callback function for asserts in the SoftDevice.
     *
     * @details This function will be called in case of an assert in the SoftDevice.
     *
     * @warning This handler is an example only and does not fit a final product. You need to analyze
     *          how your product is supposed to react in case of Assert.
     * @warning On assert from the SoftDevice, the system can only recover on reset.
     *
     * @param[in] line_num   Line number of the failing ASSERT call.
     * @param[in] file_name  File name of the failing ASSERT call.
     */
    void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
    {
        app_error_handler(DEAD_BEEF, line_num, p_file_name);
    }
    
    
    /**@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)
    {
        pm_handler_on_pm_evt(p_evt);
        pm_handler_disconnect_on_sec_failure(p_evt);
        pm_handler_flash_clean(p_evt);
    
        switch (p_evt->evt_id)
        {
            case PM_EVT_PEERS_DELETE_SUCCEEDED:
                advertising_start(false);
                break;
    
            default:
                break;
        }
    }
    
    
    /**@brief Function for the Timer initialization.
     *
     * @details Initializes the timer module. This creates and starts application timers.
     */
    static void timers_init(void)
    {
        // Initialize timer module.
        ret_code_t err_code = app_timer_init();
        APP_ERROR_CHECK(err_code);
    
        // Create timers.
    
        /* YOUR_JOB: Create any timers to be used by the application.
                     Below is an example of how to create a timer.
                     For every new timer needed, increase the value of the macro APP_TIMER_MAX_TIMERS by
                     one.
           ret_code_t err_code;
           err_code = app_timer_create(&m_app_timer_id, APP_TIMER_MODE_REPEATED, timer_timeout_handler);
           APP_ERROR_CHECK(err_code); */
    }
    
    
    /**@brief Function for the GAP initialization.
     *
     * @details This function sets up all the necessary GAP (Generic Access Profile) parameters of the
     *          device including the device name, appearance, and the preferred connection parameters.
     */
    static void gap_params_init(void)
    {
        ret_code_t              err_code;
        ble_gap_conn_params_t   gap_conn_params;
        ble_gap_conn_sec_mode_t sec_mode;
    
        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
    
        err_code = sd_ble_gap_device_name_set(&sec_mode,
                                              (const uint8_t *)DEVICE_NAME,
                                              strlen(DEVICE_NAME));
        APP_ERROR_CHECK(err_code);
    
        /* YOUR_JOB: Use an appearance value matching the application's use case.
           err_code = sd_ble_gap_appearance_set(BLE_APPEARANCE_);
           APP_ERROR_CHECK(err_code); */
    
        memset(&gap_conn_params, 0, sizeof(gap_conn_params));
    
        gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
        gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
        gap_conn_params.slave_latency     = SLAVE_LATENCY;
        gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;
    
        err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for initializing the GATT module.
     */
    static void gatt_init(void)
    {
        ret_code_t err_code = nrf_ble_gatt_init(&m_gatt, NULL);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling Queued Write Module errors.
     *
     * @details A pointer to this function will be passed to each service which may need to inform the
     *          application about an error.
     *
     * @param[in]   nrf_error   Error code containing information about what went wrong.
     */
    static void nrf_qwr_error_handler(uint32_t nrf_error)
    {
        APP_ERROR_HANDLER(nrf_error);
    }
    
    
    /**@brief Function for handling the YYY Service events.
     * YOUR_JOB implement a service handler function depending on the event the service you are using can generate
     *
     * @details This function will be called for all YY Service events which are passed to
     *          the application.
     *
     * @param[in]   p_yy_service   YY Service structure.
     * @param[in]   p_evt          Event received from the YY Service.
     *
     *
    static void on_yys_evt(ble_yy_service_t     * p_yy_service,
                           ble_yy_service_evt_t * p_evt)
    {
        switch (p_evt->evt_type)
        {
            case BLE_YY_NAME_EVT_WRITE:
                APPL_LOG("[APPL]: charact written with value %s. ", p_evt->params.char_xx.value.p_str);
                break;
    
            default:
                // No implementation needed.
                break;
        }
    }
    */
    
    /**@brief Function for initializing services that will be used by the application.
     */
    static void services_init(void)
    {
        ret_code_t         err_code;
        nrf_ble_qwr_init_t qwr_init = {0};
    
        // Initialize Queued Write Module.
        qwr_init.error_handler = nrf_qwr_error_handler;
    
        err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
        APP_ERROR_CHECK(err_code);
    
        /* YOUR_JOB: Add code to initialize the services used by the application.
           ble_xxs_init_t                     xxs_init;
           ble_yys_init_t                     yys_init;
    
           // Initialize XXX Service.
           memset(&xxs_init, 0, sizeof(xxs_init));
    
           xxs_init.evt_handler                = NULL;
           xxs_init.is_xxx_notify_supported    = true;
           xxs_init.ble_xx_initial_value.level = 100;
    
           err_code = ble_bas_init(&m_xxs, &xxs_init);
           APP_ERROR_CHECK(err_code);
    
           // Initialize YYY Service.
           memset(&yys_init, 0, sizeof(yys_init));
           yys_init.evt_handler                  = on_yys_evt;
           yys_init.ble_yy_initial_value.counter = 0;
    
           err_code = ble_yy_service_init(&yys_init, &yy_init);
           APP_ERROR_CHECK(err_code);
         */
    }
    
    
    /**@brief Function for handling the Connection Parameters Module.
     *
     * @details This function will be called for all events in the Connection Parameters Module which
     *          are passed to the application.
     *          @note All this function does is to disconnect. This could have been done by simply
     *                setting the disconnect_on_fail config parameter, but instead we use the event
     *                handler mechanism to demonstrate its use.
     *
     * @param[in] p_evt  Event received from the Connection Parameters Module.
     */
    static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
    {
        ret_code_t err_code;
    
        if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
        {
            err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
            APP_ERROR_CHECK(err_code);
        }
    }
    
    
    /**@brief Function for handling a Connection Parameters error.
     *
     * @param[in] nrf_error  Error code containing information about what went wrong.
     */
    static void conn_params_error_handler(uint32_t nrf_error)
    {
        APP_ERROR_HANDLER(nrf_error);
    }
    
    
    /**@brief Function for initializing the Connection Parameters module.
     */
    static void conn_params_init(void)
    {
        ret_code_t             err_code;
        ble_conn_params_init_t cp_init;
    ble_gap_conn_params_t  preferred_conn_param;
        memset(&cp_init, 0, sizeof(cp_init));
    
        cp_init.p_conn_params                  = NULL;
        cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
        cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
        cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
        cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
        cp_init.disconnect_on_fail             = false;
        cp_init.evt_handler                    = on_conn_params_evt;
        cp_init.error_handler                  = conn_params_error_handler;
    
        err_code = ble_conn_params_init(&cp_init);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for starting timers.
     */
    static void application_timers_start(void)
    {
        /* YOUR_JOB: Start your timers. below is an example of how to start a timer.
           ret_code_t err_code;
           err_code = app_timer_start(m_app_timer_id, TIMER_INTERVAL, NULL);
           APP_ERROR_CHECK(err_code); */
    
    }
    
    
    /**@brief Function for putting the chip into sleep mode.
     *
     * @note This function will not return.
     */
    static void sleep_mode_enter(void)
    {
        ret_code_t err_code;
    
        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);
    }
    
    
    /**@brief Function for handling advertising events.
     *
     * @details This function will be called for advertising events which are passed to the application.
     *
     * @param[in] ble_adv_evt  Advertising event.
     */
    static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
    {
        ret_code_t err_code;
    
        switch (ble_adv_evt)
        {
            case BLE_ADV_EVT_FAST:
                NRF_LOG_INFO("Fast advertising.");
                err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_ADV_EVT_IDLE:
                sleep_mode_enter();
                break;
    
            default:
                break;
        }
    }
    
    
    /**@brief Function for handling BLE events.
     *
     * @param[in]   p_ble_evt   Bluetooth stack event.
     * @param[in]   p_context   Unused.
     */
    static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
    {
        ret_code_t err_code = NRF_SUCCESS;
    
        switch (p_ble_evt->header.evt_id)
        {
            case BLE_GAP_EVT_DISCONNECTED:
                NRF_LOG_INFO("Disconnected.");
                // LED indication will be changed when advertising starts.
                break;
    
            case BLE_GAP_EVT_CONNECTED:
                NRF_LOG_INFO("Connected.");
                err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
                APP_ERROR_CHECK(err_code);
                m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
                err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
            {
                NRF_LOG_DEBUG("PHY update request.");
                ble_gap_phys_t const phys =
                {
                    .rx_phys = BLE_GAP_PHY_AUTO,
                    .tx_phys = BLE_GAP_PHY_AUTO,
                };
                err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
                APP_ERROR_CHECK(err_code);
            } break;
    
            case BLE_GATTC_EVT_TIMEOUT:
                // Disconnect on GATT Client timeout event.
                NRF_LOG_DEBUG("GATT Client Timeout.");
                err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
                                                 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                APP_ERROR_CHECK(err_code);
                break;
    
            case BLE_GATTS_EVT_TIMEOUT:
                // Disconnect on GATT Server timeout event.
                NRF_LOG_DEBUG("GATT Server Timeout.");
                err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                                 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                APP_ERROR_CHECK(err_code);
                break;
    
            default:
                // No implementation needed.
                break;
        }
    }
    
    
    /**@brief Function for initializing the BLE stack.
     *
     * @details Initializes the SoftDevice and the BLE event interrupt.
     */
    static void ble_stack_init(void)
    {
        ret_code_t err_code;
    
        err_code = nrf_sdh_enable_request();
        APP_ERROR_CHECK(err_code);
    
        // Configure the BLE stack using the default settings.
        // Fetch the start address of the application RAM.
        uint32_t ram_start = 0;
        err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
        APP_ERROR_CHECK(err_code);
    
        // Enable BLE stack.
        err_code = nrf_sdh_ble_enable(&ram_start);
        APP_ERROR_CHECK(err_code);
    
        // Register a handler for BLE events.
        NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
    }
    
    
    /**@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 Clear bond information from persistent storage.
     */
    static void delete_bonds(void)
    {
        ret_code_t err_code;
    
        NRF_LOG_INFO("Erase bonds!");
    
        err_code = pm_peers_delete();
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling events from the BSP module.
     *
     * @param[in]   event   Event generated when button is pressed.
     */
    static void bsp_event_handler(bsp_event_t event)
    {
        ret_code_t err_code;
    
        switch (event)
        {
            case BSP_EVENT_SLEEP:
                sleep_mode_enter();
                break; // BSP_EVENT_SLEEP
    
            case BSP_EVENT_DISCONNECT:
                err_code = sd_ble_gap_disconnect(m_conn_handle,
                                                 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
                break; // BSP_EVENT_DISCONNECT
    
            case BSP_EVENT_WHITELIST_OFF:
                if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
                {
                    err_code = ble_advertising_restart_without_whitelist(&m_advertising);
                    if (err_code != NRF_ERROR_INVALID_STATE)
                    {
                        APP_ERROR_CHECK(err_code);
                    }
                }
                break; // BSP_EVENT_KEY_0
    
            default:
                break;
        }
    }
    
    
    /**@brief Function for initializing the Advertising functionality.
     */
    static void advertising_init(void)
    {
        ret_code_t             err_code;
        ble_advertising_init_t init;
    
        memset(&init, 0, sizeof(init));
    
        init.advdata.name_type               = BLE_ADVDATA_FULL_NAME;
        init.advdata.include_appearance      = true;
        init.advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
        init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
        init.advdata.uuids_complete.p_uuids  = m_adv_uuids;
    
        init.config.ble_adv_fast_enabled  = true;
        init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
        init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;
    
        init.evt_handler = on_adv_evt;
    
        err_code = ble_advertising_init(&m_advertising, &init);
        APP_ERROR_CHECK(err_code);
    
        ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
    }
    
    
    /**@brief Function for initializing buttons and leds.
     *
     * @param[out] p_erase_bonds  Will be true if the clear bonding button was pressed to wake the application up.
     */
    static void buttons_leds_init(bool * p_erase_bonds)
    {
        ret_code_t err_code;
        bsp_event_t startup_event;
    
        err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, bsp_event_handler);
        APP_ERROR_CHECK(err_code);
    
        err_code = bsp_btn_ble_init(NULL, &startup_event);
        APP_ERROR_CHECK(err_code);
    
        *p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
    }
    
    
    /**@brief Function for initializing the nrf log module.
     */
    static void log_init(void)
    {
        ret_code_t err_code = NRF_LOG_INIT(NULL);
        APP_ERROR_CHECK(err_code);
    
        NRF_LOG_DEFAULT_BACKENDS_INIT();
    }
    
    
    /**@brief Function for initializing power management.
     */
    static void power_management_init(void)
    {
        ret_code_t err_code;
        err_code = nrf_pwr_mgmt_init();
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling the idle state (main loop).
     *
     * @details If there is no pending log operation, then sleep until next the next event occurs.
     */
    static void idle_state_handle(void)
    {
        if (NRF_LOG_PROCESS() == false)
        {
            nrf_pwr_mgmt_run();
        }
    }
    
    
    /**@brief Function for starting advertising.
     */
    static void advertising_start(bool erase_bonds)
    {
        if (erase_bonds == true)
        {
            delete_bonds();
            // Advertising is started by PM_EVT_PEERS_DELETED_SUCEEDED event
        }
        else
        {
            ret_code_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
    
            APP_ERROR_CHECK(err_code);
        }
    }
    
    
    /**@brief Function for application main entry.
     */
    int main(void)
    {
        bool erase_bonds;
    
        // Initialize.
        log_init();
        timers_init();
        buttons_leds_init(&erase_bonds);
        power_management_init();
        ble_stack_init();
        gap_params_init();
        gatt_init();
        advertising_init();
        services_init();
        conn_params_init();
        peer_manager_init();
    
        // Start execution.
        NRF_LOG_INFO("Template example started.");
        application_timers_start();
    
        advertising_start(erase_bonds);
    
        // Enter main loop.
        for (;;)
        {
            idle_state_handle();
        }
    }
    
    
    /**
     * @}
     */
    

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