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Custom BLE error

I tried implementing the custom BLE example in the below link

Im facing two problem
    1. ble_cus.h header file throws error

Main

/**
 * Copyright (c) 2014 - 2019, Nordic Semiconductor ASA
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
/** @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"
#include "ble_cus.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                300                                     /**< 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(100, UNIT_1_25_MS)        /**< Minimum acceptable connection interval (0.1 seconds). */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)        /**< Maximum acceptable connection interval (0.2 second). */
#define SLAVE_LATENCY                   0                                       /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)         /**< Connection supervisory timeout (4 seconds). */

#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                   /**< 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. */

BLE_CUS_DEF(m_cus);
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. */
{
    {CUSTOM_SERVICE_UUID, BLE_UUID_TYPE_VENDOR_BEGIN }
};


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_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);

     ble_cus_init_t                     cus_init;

     // Initialize CUS Service init structure to zero.
    memset(&cus_init, 0, sizeof(cus_init));
	
    err_code = ble_cus_init(&m_cus, &cus_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;

    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();
    }
}


/**
 * @}
 */

ble_cus.h

/* This code belongs in ble_cus.h*/
#include <stdint.h>
#include <stdbool.h>
#include "ble.h"
#include "ble_srv_common.h"




/* This code belongs in ble_cus.h*/
#define CUSTOM_SERVICE_UUID_BASE         {0xBC, 0x8A, 0xBF, 0x45, 0xCA, 0x05, 0x50, 0xBA, \
                                          0x40, 0x42, 0xB0, 0x00, 0xC9, 0xAD, 0x64, 0xF3}



/* This code belongs in ble_cus.h*/
#define CUSTOM_SERVICE_UUID               0x1400
#define CUSTOM_VALUE_CHAR_UUID            0x1401

/* This code belongs in ble_cus.h*/

// Forward declaration of the ble_cus_t type.
typedef struct ble_cus_s ble_cus_t;



/* This code belongs in ble_cus.h*/

/**@brief   Macro for defining a ble_cus instance.
 *
 * @param   _name   Name of the instance.
 * @hideinitializer
 */
#define BLE_CUS_DEF(_name)                                                                          \
static ble_cus_t _name;    


/* This code belongs in ble_cus.h*/

/**@brief Custom Service init structure. This contains all options and data needed for
 *        initialization of the service.*/
typedef struct
{
    uint8_t                       initial_custom_value;           /**< Initial custom value */
    ble_srv_cccd_security_mode_t  custom_value_char_attr_md;     /**< Initial security level for Custom characteristics attribute */
} ble_cus_init_t;




/* This code belongs in ble_cus.h*/

/**@brief Custom Service structure. This contains various status information for the service. */
struct ble_cus_s
{
    uint16_t                      service_handle;                 /**< Handle of Custom Service (as provided by the BLE stack). */
    ble_gatts_char_handles_t      custom_value_handles;           /**< Handles related to the Custom Value characteristic. */
    uint16_t                      conn_handle;                    /**< Handle of the current connection (as provided by the BLE stack, is BLE_CONN_HANDLE_INVALID if not in a connection). */
    uint8_t                       uuid_type; 
};





/* This code belongs in ble_cus.h*/

/**@brief Function for initializing the Custom Service.
 *
 * @param[out]  p_cus       Custom Service structure. This structure will have to be supplied by
 *                          the application. It will be initialized by this function, and will later
 *                          be used to identify this particular service instance.
 * @param[in]   p_cus_init  Information needed to initialize the service.
 *
 * @return      NRF_SUCCESS on successful initialization of service, otherwise an error code.
 */
uint32_t ble_cus_init(ble_cus_t * p_cus, const ble_cus_init_t * p_cus_init);


ble_cus.c

/* This code belongs in ble_cus.c*/
#include "sdk_common.h"
#include "ble_srv_common.h"
#include "ble_cus.h"
#include <string.h>
#include "nrf_gpio.h"
#include "boards.h"
#include "nrf_log.h"





//The first thing we should do upon entering ble_cus_init is to check that none of the pointers that we passed as arguments are NULL and declare the two variables err_code and ble_uuid.
/* This code belongs in ble_cus.c*/

uint32_t ble_cus_init(ble_cus_t * p_cus, const ble_cus_init_t * p_cus_init)
{
    if (p_cus == NULL || p_cus_init == NULL)
    {
        return NRF_ERROR_NULL;
    }

    uint32_t   err_code;
    ble_uuid_t ble_uuid;




// should only be valid when we're in a connection
/* This code belongs in ble_cus_init() in ble_cus.c*/

// Initialize service structure
p_cus->conn_handle = BLE_CONN_HANDLE_INVALID;






//Next, we're going to add our custom (also referred to as vendor specific) base UUID to the BLE stack's table.
/* This code belongs in ble_cus_init() ble_cus.c*/

// Add Custom Service UUID
ble_uuid128_t base_uuid = {CUSTOM_SERVICE_UUID_BASE};
err_code =  sd_ble_uuid_vs_add(&base_uuid, &p_cus->uuid_type);
VERIFY_SUCCESS(err_code);

ble_uuid.type = p_cus->uuid_type;
ble_uuid.uuid = CUSTOM_SERVICE_UUID;





//add the Custom Service decleration to the BLE Stack's GATT table.
/* This code belongs in ble_cus_init() in ble_cus.c*/

// Add the Custom Service
err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_cus->service_handle);
    VERIFY_SUCCESS(err_code);
    
    return err_code;
}




The error is as follows

2. Cannot find the linker option stated in the example, inside project menu

  • Thank you Kenneth, that is very helpful.

    Im trying to do the "challenge" mentioned in the same tutorial.https://github.com/NordicPlayground/nRF52-Bluetooth-Course

    I have written the code as below.  No matter what value i write, the control is entering the else if statement and never Blinking led 4. From the App, i tried writting uint8 01 and byte 0x01.(Only led 2 and 3 are toggling always)

    Can you kindly guide me?

    static void on_write(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
    {
        ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
        
        // Check if the handle passed with the event matches the Custom Value Characteristic handle.
        if (p_evt_write->handle == p_cus->custom_value_handles.value_handle)
        {
           if(p_evt_write->data[1] == 0x01){// Put specific task here. 
            nrf_gpio_pin_toggle(LED_4); 
            }
            else if (p_evt_write->data[1] == 0x00){
            nrf_gpio_pin_toggle(LED_3); 
            nrf_gpio_pin_toggle(LED_2); 
            }
        }
    }

  • Thank you,

    i moved forward, STEP 8 until enabling the notification, and facing an error as below,

    Building ‘ble_app_template_pca10040_s132’ from solution ‘ble_app_template_pca10040_s132’ in configuration ‘Release’
      'Output/ble_app_template_pca10040_s132 Release/Obj/thumb_crt0.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_log_backend_rtt.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_log_backend_serial.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_log_backend_uart.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_log_default_backends.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_log_frontend.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_log_str_formatter.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_button.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_error.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_error_handler_gcc.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_error_weak.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_scheduler.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_timer.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/app_util_platform.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/crc16.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/fds.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/hardfault_implementation.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_assert.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_atfifo.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_atflags.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_atomic.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_balloc.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_fprintf.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_fprintf_format.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_fstorage.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_fstorage_sd.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_memobj.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_pwr_mgmt.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_ringbuf.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_section_iter.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_strerror.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/sensorsim.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/ses_startup_nrf52.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/ses_startup_nrf_common.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/system_nrf52.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/boards.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_drv_clock.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_drv_uart.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrfx_atomic.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrfx_clock.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrfx_gpiote.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrfx_prs.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrfx_uart.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrfx_uarte.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/bsp.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/bsp_btn_ble.o' is up to date
      ble_cus.c (27.05.2020 13:16:40) is newer than Output/ble_app_template_pca10040_s132 Release/Obj/ble_cus.o (27.05.2020 11:33:19).
      ../../../main.c (27.05.2020 13:11:35) is newer than Output/ble_app_template_pca10040_s132 Release/Obj/main.o (27.05.2020 11:07:46).
      Compiling ‘main.c’
        main.c
        unknown type name 'ble_cus_evt_handler_t'
        conflicting types for 'ble_cus_init_t'
        main.c
        previous declaration of 'ble_cus_init_t' was here
        main.c
        redefinition of 'struct ble_cus_s'
        main.c
        originally defined here
        main.c
        unknown type name 'ble_cus_evt_handler_t'
        'on_cus_evt' undeclared (first use in this function); did you mean 'on_connect'?
        each undeclared identifier is reported only once for each function it appears in
        passing argument 2 of 'ble_cus_init' from incompatible pointer type [-Wincompatible-pointer-types]
        main.c
        expected 'const ble_cus_init_t *' {aka 'const struct <anonymous> *'} but argument is of type 'ble_cus_init_t *' {aka 'struct <anonymous> *'}
      'Output/ble_app_template_pca10040_s132 Release/Obj/SEGGER_RTT.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/SEGGER_RTT_Syscalls_SES.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/SEGGER_RTT_printf.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/auth_status_tracker.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/ble_advdata.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/ble_advertising.o' is up to date
      Compiling ‘ble_cus.c’
        ble_cus.c
        unknown type name 'ble_cus_evt_handler_t'
        conflicting types for 'ble_cus_init_t'
        ble_cus.c
        previous declaration of 'ble_cus_init_t' was here
        ble_cus.c
        redefinition of 'struct ble_cus_s'
        ble_cus.c
        originally defined here
        ble_cus.c
        unknown type name 'ble_cus_evt_handler_t'
        conflicting types for 'ble_cus_init'
        ble_cus.c
        previous declaration of 'ble_cus_init' was here
        'ble_cus_t' {aka 'struct ble_cus_s'} has no member named 'evt_handler'; did you mean 'conn_handle'?
        passing argument 2 of 'custom_value_char_add' from incompatible pointer type [-Wincompatible-pointer-types]
        ble_cus.c
        expected 'const ble_cus_init_t *' {aka 'const struct <anonymous> *'} but argument is of type 'const ble_cus_init_t *' {aka 'const struct <anonymous> *'}
        conflicting types for 'custom_value_char_add'
        ble_cus.c
        previous declaration of 'custom_value_char_add' was here
        'ble_cus_t' {aka 'struct ble_cus_s'} has no member named 'evt_handler'; did you mean 'conn_handle'?
        initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
        'ble_cus_t' {aka 'struct ble_cus_s'} has no member named 'evt_handler'; did you mean 'conn_handle'?
        'ble_cus_t' {aka 'struct ble_cus_s'} has no member named 'evt_handler'; did you mean 'conn_handle'?
        ble_cus.c
        'custom_value_char_add' used but never defined
      'Output/ble_app_template_pca10040_s132 Release/Obj/ble_conn_params.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/ble_conn_state.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/ble_srv_common.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/gatt_cache_manager.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/gatts_cache_manager.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/id_manager.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_ble_gatt.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_ble_qwr.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/peer_data_storage.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/peer_database.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/peer_id.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/peer_manager.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/peer_manager_handler.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/pm_buffer.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/security_dispatcher.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/security_manager.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/utf.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_sdh.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_sdh_ble.o' is up to date
      'Output/ble_app_template_pca10040_s132 Release/Obj/nrf_sdh_soc.o' is up to date
    Build failed

    I cant find the definition of this, ble_cus_evt_handler_t. it has been used in 2 structures.

    The files im using are as below.

    /* This code belongs in ble_cus.c*/
    #include "sdk_common.h"
    #include "ble_srv_common.h"
    #include "ble_cus.h"
    #include <string.h>
    #include "nrf_gpio.h"
    #include "boards.h"
    #include "nrf_log.h"
    
    
    
    
    
    //The first thing we should do upon entering ble_cus_init is to check that none of the pointers that we passed as arguments are NULL and declare the two variables err_code and ble_uuid.
    /* This code belongs in ble_cus.c*/
    
    uint32_t ble_cus_init(ble_cus_t * p_cus, const ble_cus_init_t * p_cus_init)
    {
        if (p_cus == NULL || p_cus_init == NULL)
        {
            return NRF_ERROR_NULL;
        }
    
        uint32_t   err_code;
        ble_uuid_t ble_uuid;
    
    
    
    //Next, we're going to add our custom (also referred to as vendor specific) base UUID to the BLE stack's table.
    /* This code belongs in ble_cus_init() ble_cus.c*/
    
    // Add Custom Service UUID
    ble_uuid128_t base_uuid = {CUSTOM_SERVICE_UUID_BASE};
    err_code =  sd_ble_uuid_vs_add(&base_uuid, &p_cus->uuid_type);
    VERIFY_SUCCESS(err_code);
    
    ble_uuid.type = p_cus->uuid_type;
    ble_uuid.uuid = CUSTOM_SERVICE_UUID;
    
    // should only be valid when we're in a connection
    /* This code belongs in ble_cus_init() in ble_cus.c*/
    
    // Initialize service structure
    p_cus->evt_handler = p_cus_init->evt_handler;
    p_cus->conn_handle = BLE_CONN_HANDLE_INVALID;
    
    
    
    //add the Custom Service decleration to the BLE Stack's GATT table.
    /* This code belongs in ble_cus_init() in ble_cus.c*/
    
    // Add the Custom Service
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_cus->service_handle);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    
    
     return custom_value_char_add(p_cus, p_cus_init);
    }
    
    
    
    
    ///////////////////////////////////////////////////////////////////////////////////////////////////////////////
    
    
    
    
    
    /* This code belongs in ble_cus.c*/
    
    /**@brief Function for adding the Custom Value characteristic.
     *
     * @param[in]   p_cus        Custom Service structure.
     * @param[in]   p_cus_init   Information needed to initialize the service.
     *
     * @return      NRF_SUCCESS on success, otherwise an error code.
     */
    static uint32_t custom_value_char_add(ble_cus_t * p_cus, const ble_cus_init_t * p_cus_init)
    {
        uint32_t            err_code;
        ble_gatts_char_md_t char_md;
        ble_gatts_attr_md_t cccd_md;
        ble_gatts_attr_t    attr_char_value;
        ble_uuid_t          ble_uuid;
        ble_gatts_attr_md_t attr_md;
    
    
    /* This code belongs in custom_value_char_add() in ble_cus.c*/
    
        memset(&cccd_md, 0, sizeof(cccd_md));
    
        //  Read  operation on Cccd should be possible without authentication.
        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
        
        cccd_md.vloc       = BLE_GATTS_VLOC_STACK;
    
    
    
    //Now starts the rather tedious part of populating all these variables, we'll start with char_md, which sets the properties that will be displayed to the central during service discovery.
    
    
    /* This code belongs in custom_value_char_add() in ble_cus.c*/
    
        memset(&char_md, 0, sizeof(char_md));
    
        char_md.char_props.read   = 1;
        char_md.char_props.write  = 1;
        char_md.char_props.notify = 1; 
        char_md.p_char_user_desc  = NULL;
        char_md.p_char_pf         = NULL;
        char_md.p_user_desc_md    = NULL;
        char_md.p_cccd_md         = &cccd_md; 
        char_md.p_sccd_md         = NULL;
    
    
    //So we want to be able to both write and read to our Custom Value characteristic, but we do not want to enable the notify property until later. Next we're going to populate the attr_md, which actually sets the properties( i.e. accessability of the attribute).
    
        /* This code belongs in custom_value_char_add() in ble_cus.c*/
    
        memset(&attr_md, 0, sizeof(attr_md));
    
        attr_md.read_perm  = p_cus_init->custom_value_char_attr_md.read_perm;
        attr_md.write_perm = p_cus_init->custom_value_char_attr_md.write_perm;
        attr_md.vloc       = BLE_GATTS_VLOC_STACK;
        attr_md.rd_auth    = 0;
        attr_md.wr_auth    = 0;
        attr_md.vlen       = 0;
    
    
    //The permissions set in the attr_md struct should correspond with the properties set in the characteristic metadata struct char_md. We're going to provide the permissions in the Custom Service init structure that we pass to ble_cus_init in services_init(). The .vloc option is set to BLE_GATTS_VLOC_STACK as we want the characteristic to be stored in the SoftDevice RAM section and not in the Application RAM section.
    
    
    
    
    
    
    //The next variable that we have to populate is ble_uuid, which is going to hold our CUSTOM_VALUE_CHAR_UUID and is of the same type as the CUSTOM_SERVICE_UUID_BASE, i.e. vendor specific, which we specified in the .uuid_type field of Custom Service strucure when we added the CUSTOM_SERVICE_UUID_BASE to the BLE stack's table.
    
     /* This code belongs in custom_value_char_add() in ble_cus.c*/
    
        ble_uuid.type = p_cus->uuid_type;
        ble_uuid.uuid = CUSTOM_VALUE_CHAR_UUID;
    
      
    //Next, we're going to populate the attr_char_value struct, which sets the UUID, points to the attribute metadata and sets the size of the characteristic, in our case a single byte(uint8_t).
    
    
        /* This code belongs in custom_value_char_add() in ble_cus.c*/
    
        memset(&attr_char_value, 0, sizeof(attr_char_value));
    
        attr_char_value.p_uuid    = &ble_uuid;
        attr_char_value.p_attr_md = &attr_md;
        attr_char_value.init_len  = sizeof(uint8_t);
        attr_char_value.init_offs = 0;
        attr_char_value.max_len   = sizeof(uint8_t);
    
    
    
    
    
    //Finally, we're done populating structs and we can add our characteristic by calling sd_ble_gatts_characteristic_add() with the structs as arguments.
    
        /* This code belongs in custom_value_char_add() in ble_cus.c*/
    
    err_code = sd_ble_gatts_characteristic_add(p_cus->service_handle, &char_md,
                                                   &attr_char_value,
                                                   &p_cus->custom_value_handles);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    
        return NRF_SUCCESS;
     
    }
    
    
    /////////////////////////////////////////////////////////////////////////////////////////////////
    
    /* This code belongs in ble_cus.c*/
    //We're now going to implement the ble_cus_on_ble_evt event handler in ble_cus.c.Upon entry its considered good practice to check that none of the pointers that we provided as arguments are NULL.
    
    //After the NULL check we're going to add a switch-case to check which event that has been propagated to the application by the SoftDevice.
    
    
    /* This code belongs in ble_cus.c*/
    
    void ble_cus_on_ble_evt( ble_evt_t const * p_ble_evt, void * p_context)
    {
        ble_cus_t * p_cus = (ble_cus_t *) p_context;
        
        if (p_cus == NULL || p_ble_evt == NULL)
        {
            return;
        }
        
        switch (p_ble_evt->header.evt_id)
        {
            case BLE_GAP_EVT_CONNECTED:
                 on_connect(p_cus, p_ble_evt);
                break;
    
            case BLE_GAP_EVT_DISCONNECTED:
                 on_disconnect(p_cus, p_ble_evt);
                break;
            case BLE_GATTS_EVT_WRITE:
               on_write(p_cus, p_ble_evt);
               break;
            default:
                // No implementation needed.
                break;
        }
    }
    
    
    //For now we only need to care about the BLE_GAP_EVT_CONNECTED and BLE_GAP_EVT_DISCONNECTED events. So let's create the two functions on_connect() and on_disconnect(), starting with on_connect(). The only thing we need to do when we get the Connect event is to assign the connection handle in the Custom Service structure to the connection handle that is passed with the event.
    
    
    /* This code belongs in ble_cus.c*/
    
    /**@brief Function for handling the Connect event.
     *
     * @param[in]   p_cus       Custom Service structure.
     * @param[in]   p_ble_evt   Event received from the BLE stack.
     */
    static void on_connect(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
    {
        p_cus->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
        ble_cus_evt_t evt;
    
        evt.evt_type = BLE_CUS_EVT_CONNECTED;
    
        p_cus->evt_handler(p_cus, &evt);
    }
    
    /* This code belongs in ble_cus.c*/
    
    /**@brief Function for handling the Disconnect event.
     *
     * @param[in]   p_cus       Custom Service structure.
     * @param[in]   p_ble_evt   Event received from the BLE stack.
     */
    static void on_disconnect(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
    {
        UNUSED_PARAMETER(p_ble_evt);
        p_cus->conn_handle = BLE_CONN_HANDLE_INVALID;
    }
    
    
    
    
    
    ////////////////////////////////////////////////////////////////////////////////////////////////////
    
    
    /* This code belongs in ble_cus.c*/
    
    /**@brief Function for handling the Write event.
     *
     * @param[in]   p_cus       Custom Service structure.
     * @param[in]   p_ble_evt   Event received from the BLE stack.
     */
    static void on_write(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
    {
        ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
        
        // Check if the handle passed with the event matches the Custom Value Characteristic handle.
        if (p_evt_write->handle == p_cus->custom_value_handles.value_handle)
        {
           if(p_evt_write->data == 0x01){                   // Put specific task here. 
            nrf_gpio_pin_toggle(LED_4); 
            }
            else if (p_evt_write->data == 0x00){
            nrf_gpio_pin_toggle(LED_3); 
            }
        }
    
            if ((p_evt_write->handle == p_cus->custom_value_handles.cccd_handle) && (p_evt_write->len == 2))
           
        {
    
            // CCCD written, call application event handler
            if (p_cus->evt_handler != NULL)
            {
                ble_cus_evt_t evt;
    
                if (ble_srv_is_notification_enabled(p_evt_write->data))
                {
                    evt.evt_type = BLE_CUS_EVT_NOTIFICATION_ENABLED;
                }
                else
                {
                    evt.evt_type = BLE_CUS_EVT_NOTIFICATION_DISABLED;
                }
                // Call the application event handler.
                p_cus->evt_handler(p_cus, &evt);
            }
    
        }
    
    }
    
     /* This code belongs in ble_cus.c*/
    
    uint32_t ble_cus_custom_value_update(ble_cus_t * p_cus, uint8_t custom_value){
        NRF_LOG_INFO("In ble_cus_custom_value_update. \r\n"); 
        if (p_cus == NULL)
        {
            return NRF_ERROR_NULL;
        }
    
    
       /* This code belongs in ble_cus_custom_value_update() in ble_cus.c*/
    
    uint32_t err_code = NRF_SUCCESS;
    ble_gatts_value_t gatts_value;
    
    // Initialize value struct.
    memset(&gatts_value, 0, sizeof(gatts_value));
    
    gatts_value.len     = sizeof(uint8_t);
    gatts_value.offset  = 0;
    gatts_value.p_value = &custom_value;
    
    // Update database.
    err_code = sd_ble_gatts_value_set(p_cus->conn_handle,
                                        p_cus->custom_value_handles.value_handle,
                                        &gatts_value);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    
    /* This code belongs in ble_cus_custom_value_update() in ble_cus.c*/
    
    // Send value if connected and notifying.
    if ((p_cus->conn_handle != BLE_CONN_HANDLE_INVALID)) 
    {
        ble_gatts_hvx_params_t hvx_params;
    
        memset(&hvx_params, 0, sizeof(hvx_params));
    
        hvx_params.handle = p_cus->custom_value_handles.value_handle;
        hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
        hvx_params.offset = gatts_value.offset;
        hvx_params.p_len  = &gatts_value.len;
        hvx_params.p_data = gatts_value.p_value;
    
        err_code = sd_ble_gatts_hvx(p_cus->conn_handle, &hvx_params);
    }
    else
    {
        err_code = NRF_ERROR_INVALID_STATE;
    }
    
    return err_code;
    
    
    
    }
    
    

    4478.ble_cus.h

    /**
     * Copyright (c) 2014 - 2019, Nordic Semiconductor ASA
     *
     * All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without modification,
     * are permitted provided that the following conditions are met:
     *
     * 1. Redistributions of source code must retain the above copyright notice, this
     *    list of conditions and the following disclaimer.
     *
     * 2. Redistributions in binary form, except as embedded into a Nordic
     *    Semiconductor ASA integrated circuit in a product or a software update for
     *    such product, must reproduce the above copyright notice, this list of
     *    conditions and the following disclaimer in the documentation and/or other
     *    materials provided with the distribution.
     *
     * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
     *    contributors may be used to endorse or promote products derived from this
     *    software without specific prior written permission.
     *
     * 4. This software, with or without modification, must only be used with a
     *    Nordic Semiconductor ASA integrated circuit.
     *
     * 5. Any software provided in binary form under this license must not be reverse
     *    engineered, decompiled, modified and/or disassembled.
     *
     * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
     * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
     * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
     * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
     * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     */
    /** @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"
    #include "ble_cus.h"
    
    
    
    #define DEVICE_NAME                     "BLE"                       /**< 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                300                                     /**< 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(100, UNIT_1_25_MS)        /**< Minimum acceptable connection interval (0.1 seconds). */
    #define MAX_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)        /**< Maximum acceptable connection interval (0.2 second). */
    #define SLAVE_LATENCY                   0                                       /**< Slave latency. */
    #define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)         /**< Connection supervisory timeout (4 seconds). */
    
    #define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                   /**< 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. */
    
    BLE_CUS_DEF(m_cus);
    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. */
    {
        {CUSTOM_SERVICE_UUID, BLE_UUID_TYPE_VENDOR_BEGIN }
    };
    
    
    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_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);
    
        /* This code belongs in services_init() in main.c*/
    
    
    
         ble_cus_init_t                     cus_init;
     /* This code belongs in services_init in main.c*/
    
        // Set the cus event handler
        cus_init.evt_handler                = on_cus_evt;
    
         // Initialize CUS Service init structure to zero.
        memset(&cus_init, 0, sizeof(cus_init));
    
        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cus_init.custom_value_char_attr_md.read_perm);
        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cus_init.custom_value_char_attr_md.write_perm);
    	
        err_code = ble_cus_init(&m_cus, &cus_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;
    
        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);
        }
    }
    
    
    /* This code belongs in main.c*/
    
    /**@brief Function for handling the Custom Service Service events.
     *
     * @details This function will be called for all Custom Service events which are passed to
     *          the application.
     *
     * @param[in]   p_cus_service  Custom Service structure.
     * @param[in]   p_evt          Event received from the Custom Service.
     *
     */
    static void on_cus_evt(ble_cus_t     * p_cus_service,
                           ble_cus_evt_t * p_evt)
    {
        switch(p_evt->evt_type)
        {
            case BLE_CUS_EVT_NOTIFICATION_ENABLED:
                break;
    
            case BLE_CUS_EVT_NOTIFICATION_DISABLED:
                break;
            case BLE_CUS_EVT_CONNECTED:
                break;
    
            case BLE_CUS_EVT_DISCONNECTED:
                break;
    
            default:
                  // No implementation needed.
                  break;
        }
    }
    
    
    
    
    
    
    
    
    
    /**@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();
        services_init();
        advertising_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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