nRF52840 DK, implementing Board Button event handler, but no response on button press.

[Paarth_Ved23]

Hi, 

I am trying to do some tasks based on a particular button press, below attached is the buttons_init() function and the button_evt_handler() function. Code compiles and runs successfully, but nothing happens on button press. Please let me know if I am missing out on something. 

Thanks in advance.

static void buttons_init(void)
{
    uint32_t err_code;

    static app_button_cfg_t buttons[] = 
    { 
        {BSP_BUTTON_0, false, BUTTON_PULL, button_evt_handler},
        {BSP_BUTTON_1, false, BUTTON_PULL, button_evt_handler}
    };

    err_code = app_button_init(buttons, ARRAY_SIZE(buttons), BUTTON_DEBOUNCE_DELAY);
    APP_ERROR_CHECK(err_code);

    err_code = app_button_enable();
    APP_ERROR_CHECK(err_code);
}    

static void button_evt_handler(uint8_t pin_no, uint8_t button_action)
{
    if(button_action == APP_BUTTON_PUSH)
    {
        switch(pin_no)
        {
            case BSP_BUTTON_0:
                NRF_LOG_INFO("Sending blood pressure data\r\n");
                break;
            case BSP_BUTTON_1:
                NRF_LOG_INFO("Sending temperature data\r\n");
                break;
            default:
                NRF_LOG_INFO("Default case\r\n");
                break;
        }
        
    }
}

[rmptxf]

Hi Paarth_Ved23,

Here is a better way to do it!

#define UART_PRINTING_ENABLED   // comment it to disable the uart logging

static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
  ret_code_t err_code;

  switch(pin_no)
  {
   case BUTTON_1:
     if(button_action == APP_BUTTON_PUSH) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button1 pressed.");
        #endif
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button1 released.");
        #endif
     }
     break;

   case BUTTON_2:
     if(button_action == APP_BUTTON_PUSH) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button2 pressed.");
        #endif
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button2 released.");
        #endif
     }
     break;

   case BUTTON_3:
     if(button_action == APP_BUTTON_PUSH) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button3 pressed.");
        #endif
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button3 released.");
        #endif
     }
     break;

   case BUTTON_4:
     if(button_action == APP_BUTTON_PUSH) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button4 pressed.");
        #endif
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        #ifdef UART_PRINTING_ENABLED
        NRF_LOG_INFO("button4 released.");
        #endif
     }
     break;
     default:
        return; // no implementation needed
  }

}

/**@brief Function for buttons configuration.
 *
 */
static const app_button_cfg_t app_buttons[BUTTONS_NUMBER] = 
{
// BUTTONS_NUMBER,
// BUTTON_PIN,
// BUTTONS_ACTIVE_STATE,
// BUTTON_PULL,
// are all declared in your components/boards/Ppca10056.h file

    {BUTTON_1, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler},
    {BUTTON_2, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler},
    {BUTTON_3, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler},
    {BUTTON_4, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler}
}; 

/**@brief Function for initializing the buttons with the app_button library.
 *
 */
 void buttons_init(){

    ret_code_t  err_code;                        
// BUTTONS_NUMBER  is declared in your components/boards/Ppca10056.h file
    err_code = app_button_init((app_button_cfg_t *)app_buttons,
                                                BUTTONS_NUMBER,
                                         BUTTON_DETECTION_TIME);
    APP_ERROR_CHECK(err_code);

    err_code = app_button_enable();
    APP_ERROR_CHECK(err_code);

}

Make sure you initialize the timer before calling the buttons_init() in the main.

/**
 *@brief Function for initialising the timers. 
 * It is necessary for the buttons to work when using the app_button library. 
 */
static void timers_init(void)
{
    // Initialize timer module.
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}

    timers_init();
    leds_init();
    buttons_init();

Also make sure to enable the app button module in the sdk_config.h file.

// <q> BUTTON_ENABLED  - Enables Button module
 

#ifndef BUTTON_ENABLED
#define BUTTON_ENABLED 1
#endif

And here is 4 key keyboard based off the nRF52840-DK. You can test it, or just re-use the button handling part for your case.

The github repos

Best regards,

rmptxf

[Paarth_Ved23]

Hi, 

Thanks for your response, I tried to implement it using the code snippets you have provided. But still no response on button press. I have tried the following:

1. Changed the button_event_handler as per the above.

2. Changed the app_button_cfg_t structure to as defined above

3. Called timer_init() before buttons_init()

4. BUTTON_ENABLED was already set. 

Also, as a footnote, I am implementing this button handler along with a bsp_event_handler already defined, would it be affecting this handler or are they completely independent? Please let me know.

Thanks again,

Paarth

[rmptxf]

Hi,

How do you check whether a button is responding or not ? I mean, in the code snippet you provided, you're using the nRF logging. Is the uart logging already working ?

What bsp events the bsp_event_handler is used for ?  for handling the buttons events too ?

regards,

rmptxf

[Paarth_Ved23]

Hi, 

The bsp_event_handler is handling BSP_EVENT_SLEEP,  BSP_EVENT_DISCONNECT and BSP_EVENT_WHITELIST_OFF.

rmptxf said:

ou're using the nRF logging. Is the uart logging already working ?

I am only using the nRF logs for debugging. 

Thanks again, 

Paarth

[rmptxf]

Hi,

Would you mind sending your project files here, or email them. To look into the issue ?

Best regards,

[Paarth_Ved23]

Sure, i have added to the ble_app_template example, here is the main.c:

Fullscreen 84216.main.c Download

/**
 * Copyright (c) 2014 - 2018, 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.
 * 
 */
 
#include <stdint.h>
#include <string.h>
#include "our_service.h"
#include "ble_srv_common.h"
#include "app_error.h"
#include "SEGGER_RTT.h"

/** @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 "app_button.h"
#include "fds.h"
#include "peer_manager.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                     "OurService"                            /**< 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                50                                      /**< 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. */

#define BUTTON_DEBOUNCE_DELAY           APP_TIMER_TICKS(50)
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. */

// STEP 1: Declare a ble_os_t service structure for our application
ble_os_t m_our_service;
// STEP 5: Declare variable holding our service UUID

static ble_uuid_t m_adv_uuids[] = 
{
    {
        BLE_UUID_OUR_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 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 handling Peer Manager events.
 *
 * @param[in] p_evt  Peer Manager event.
 */
static void pm_evt_handler(pm_evt_t const * p_evt)
{
    ret_code_t err_code;

    switch (p_evt->evt_id)
    {
        case PM_EVT_BONDED_PEER_CONNECTED:
        {
            NRF_LOG_INFO("Connected to a previously bonded device.");
        } break;

        case PM_EVT_CONN_SEC_SUCCEEDED:
        {
            NRF_LOG_INFO("Connection secured: role: %d, conn_handle: 0x%x, procedure: %d.",
                         ble_conn_state_role(p_evt->conn_handle),
                         p_evt->conn_handle,
                         p_evt->params.conn_sec_succeeded.procedure);
        } break;

        case PM_EVT_CONN_SEC_FAILED:
        {
            /* Often, when securing fails, it shouldn't be restarted, for security reasons.
             * Other times, it can be restarted directly.
             * Sometimes it can be restarted, but only after changing some Security Parameters.
             * Sometimes, it cannot be restarted until the link is disconnected and reconnected.
             * Sometimes it is impossible, to secure the link, or the peer device does not support it.
             * How to handle this error is highly application dependent. */
        } break;

        case PM_EVT_CONN_SEC_CONFIG_REQ:
        {
            // Reject pairing request from an already bonded peer.
            pm_conn_sec_config_t conn_sec_config = {.allow_repairing = false};
            pm_conn_sec_config_reply(p_evt->conn_handle, &conn_sec_config);
        } break;

        case PM_EVT_STORAGE_FULL:
        {
            // Run garbage collection on the flash.
            err_code = fds_gc();
            if (err_code == FDS_ERR_NO_SPACE_IN_QUEUES)
            {
                // Retry.
            }
            else
            {
                APP_ERROR_CHECK(err_code);
            }
        } break;

        case PM_EVT_PEERS_DELETE_SUCCEEDED:
        {
            advertising_start(false);
        } break;

        case PM_EVT_PEER_DATA_UPDATE_FAILED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.peer_data_update_failed.error);
        } break;

        case PM_EVT_PEER_DELETE_FAILED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.peer_delete_failed.error);
        } break;

        case PM_EVT_PEERS_DELETE_FAILED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.peers_delete_failed_evt.error);
        } break;

        case PM_EVT_ERROR_UNEXPECTED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.error_unexpected.error);
        } break;

        case PM_EVT_CONN_SEC_START:
        case PM_EVT_PEER_DATA_UPDATE_SUCCEEDED:
        case PM_EVT_PEER_DELETE_SUCCEEDED:
        case PM_EVT_LOCAL_DB_CACHE_APPLIED:
        case PM_EVT_LOCAL_DB_CACHE_APPLY_FAILED:
            // This can happen when the local DB has changed.
        case PM_EVT_SERVICE_CHANGED_IND_SENT:
        case PM_EVT_SERVICE_CHANGED_IND_CONFIRMED:
        default:
            break;
    }
}


/**@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);

    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 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 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 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);
	
    // STEP 2: Add code to initialize the services used by the application.
    our_service_init(&m_our_service);
}


/**@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);
    NRF_SDH_BLE_OBSERVER(m_our_service_observer, APP_BLE_OBSERVER_PRIO, ble_our_service_on_ble_evt, (void *)&m_our_service);
}


/**@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;
    
	// STEP 6: Declare and instantiate the scan response
    init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.srdata.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);
}

void send_string()
{
   
}
static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
  ret_code_t err_code;

  switch(pin_no)
  {
   case BUTTON_1:
     if(button_action == APP_BUTTON_PUSH) {
        //Send BP data
        
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        NRF_LOG_INFO("button1 released.");
     }
     break;

   case BUTTON_2:
     if(button_action == APP_BUTTON_PUSH) {
        int32_t temperature = 0;
        sd_temp_get(&temperature);
        our_temperature_characteristic_update(&m_our_service, &temperature);
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        NRF_LOG_INFO("button2 released.");
     }
     break;

   case BUTTON_3:
     if(button_action == APP_BUTTON_PUSH) {
        send_string();
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        NRF_LOG_INFO("button3 released.");
     }
     break;

   case BUTTON_4:
     if(button_action == APP_BUTTON_PUSH) {
        NRF_LOG_INFO("button4 pressed.");
     }
     else if(button_action == APP_BUTTON_RELEASE) {
        NRF_LOG_INFO("button4 released.");
     }
     break;
     default:
        return; // no implementation needed
  }
}

/**@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_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);
}

static const app_button_cfg_t buttons[BUTTONS_NUMBER] = 
{ 
    {BUTTON_1, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler},
    {BUTTON_2, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler},
    {BUTTON_3, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler},
    {BUTTON_4, BUTTONS_ACTIVE_STATE, BUTTON_PULL, button_event_handler}
};
static void buttons_init(void)
{
    ret_code_t err_code;
    
    err_code = app_button_init((app_button_cfg_t *)buttons, BUTTONS_NUMBER, BUTTON_DEBOUNCE_DELAY);
    APP_ERROR_CHECK(err_code);

    err_code = app_button_enable();
    APP_ERROR_CHECK(err_code);
}    


/**@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;
    nrf_gpio_pin_dir_set(LED_1, NRF_GPIO_PIN_DIR_OUTPUT);
    // Initialize.
    log_init();
	timers_init();
    buttons_leds_init(&erase_bonds);
    buttons_init();
    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("started.");
    application_timers_start();

    advertising_start(erase_bonds);

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

2. our_service.c: For a custom service and characteristics:

Fullscreen 6116.our_service.c Download

/**
 * Copyright (c) 2014 - 2018, 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.
 * 
 */

#include <stdint.h>
#include <string.h>
#include "our_service.h"
#include "ble_srv_common.h"
#include "app_error.h"
#include "SEGGER_RTT.h"

void ble_our_service_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context)
{
  	ble_os_t * p_our_service =(ble_os_t *) p_context;  
		// OUR_JOB: Step 3.D Implement switch case handling BLE events related to our service. 
	switch (p_ble_evt->header.evt_id)
        {
            case BLE_GAP_EVT_CONNECTED:
                p_our_service->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
                break;
            case BLE_GAP_EVT_DISCONNECTED:
                p_our_service->conn_handle = BLE_CONN_HANDLE_INVALID;
                break;
            default:
                // No implementation needed.
                 break;
        }
	
}

/**@brief Function for adding our new characterstic to "Our service" that we initiated in the previous tutorial. 
 *
 * @param[in]   p_our_service        Our Service structure.
 *
 */
static uint32_t our_char_add(ble_os_t * p_our_service)
{
    // OUR_JOB: Step 2.A, Add a custom characteristic UUID
    uint32_t          err_code;
    ble_uuid_t        char_uuid;
    ble_uuid128_t     base_uuid = BLE_UUID_OUR_BASE_UUID;
    char_uuid.uuid = BLE_UUID_OUR_CHARACTERISTC_UUID;

    err_code = sd_ble_uuid_vs_add(&base_uuid, &char_uuid.type);
    APP_ERROR_CHECK(err_code);

    
    // OUR_JOB: Step 2.F Add read/write properties to our characteristic
    ble_gatts_char_md_t char_md;
    memset(&char_md, 0, sizeof(char_md));
    char_md.char_props.read = 1;
    char_md.char_props.write = 1;



    
    // OUR_JOB: Step 3.A, Configuring Client Characteristic Configuration Descriptor metadata and add to char_md structure
    ble_gatts_attr_md_t cccd_md;
    memset(&cccd_md, 0, sizeof(cccd_md));
    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;
    char_md.p_cccd_md = &cccd_md;
    char_md.char_props.notify = 1;

   
    
    // OUR_JOB: Step 2.B, Configure the attribute metadata
    ble_gatts_attr_md_t attr_md;
    memset(&attr_md, 0, sizeof(attr_md));  
    attr_md.vloc = BLE_GATTS_VLOC_STACK;
    
	
    
    
    // OUR_JOB: Step 2.G, Set read/write security levels to our characteristic
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

    // OUR_JOB: Step 2.C, Configure the characteristic value attribute
    ble_gatts_attr_t    attr_char_value;
    memset(&attr_char_value, 0, sizeof(attr_char_value));
    attr_char_value.p_uuid = &char_uuid;
    attr_char_value.p_attr_md = &attr_md;


    
    // OUR_JOB: Step 2.H, Set characteristic length in number of bytes
    attr_char_value.max_len = 4;
    attr_char_value.init_len = 4;
    uint8_t value[4] = {0x12, 0x34, 0x56, 0x78};
    attr_char_value.p_value = value;

    // OUR_JOB: Step 2.E, Add our new characteristic to the service
    err_code = sd_ble_gatts_characteristic_add(p_our_service->service_handle, &char_md, &attr_char_value, &p_our_service->char_handles);
    APP_ERROR_CHECK(err_code);

    return NRF_SUCCESS;
}

static uint32_t our_char_bp_add(ble_os_t * p_our_service)
{
    // OUR_JOB: Step 2.A, Add a custom characteristic UUID
    uint32_t          err_code;
    ble_uuid_t        char_uuid;
    ble_uuid128_t     base_uuid = BLE_UUID_OUR_BASE_UUID;
    char_uuid.uuid = BLE_UUID_BP_CHARACTERISTIC;

    err_code = sd_ble_uuid_vs_add(&base_uuid, &char_uuid.type);
    APP_ERROR_CHECK(err_code);

    
    // OUR_JOB: Step 2.F Add read/write properties to our characteristic
    ble_gatts_char_md_t char_md;
    memset(&char_md, 0, sizeof(char_md));
    char_md.char_props.read = 1;
    char_md.char_props.write = 1;



    
    // OUR_JOB: Step 3.A, Configuring Client Characteristic Configuration Descriptor metadata and add to char_md structure
    ble_gatts_attr_md_t cccd_md;
    memset(&cccd_md, 0, sizeof(cccd_md));
    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;
    char_md.p_cccd_md = &cccd_md;
    char_md.char_props.notify = 1;

   
    
    // OUR_JOB: Step 2.B, Configure the attribute metadata
    ble_gatts_attr_md_t attr_md;
    memset(&attr_md, 0, sizeof(attr_md));  
    attr_md.vloc = BLE_GATTS_VLOC_STACK;
    
	
    
    
    // OUR_JOB: Step 2.G, Set read/write security levels to our characteristic
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

    // OUR_JOB: Step 2.C, Configure the characteristic value attribute
    ble_gatts_attr_t    attr_char_value;
    memset(&attr_char_value, 0, sizeof(attr_char_value));
    attr_char_value.p_uuid = &char_uuid;
    attr_char_value.p_attr_md = &attr_md;


    
    // OUR_JOB: Step 2.H, Set characteristic length in number of bytes
    attr_char_value.max_len = 4;
    attr_char_value.init_len = 4;
    uint8_t value[4] = {0x12, 0x34, 0x56, 0x78};
    attr_char_value.p_value = value;

    // OUR_JOB: Step 2.E, Add our new characteristic to the service
    err_code = sd_ble_gatts_characteristic_add(p_our_service->service_handle, &char_md, &attr_char_value, &p_our_service->char_bp_handles);
    APP_ERROR_CHECK(err_code);

    return NRF_SUCCESS;
}
/**@brief Function for initiating our new service.
 *
 * @param[in]   p_our_service        Our Service structure.
 *
 */
void our_service_init(ble_os_t * p_our_service)
{

    // STEP 3: Declare 16 bit service and 128 bit base UUIDs and add them to BLE stack table     
    uint32_t      err_code;
    ble_uuid_t    service_uuid;
    ble_uuid128_t base_uuid = BLE_UUID_OUR_BASE_UUID;
    service_uuid.uuid = BLE_UUID_OUR_SERVICE_UUID;

    err_code = sd_ble_uuid_vs_add(&base_uuid, &service_uuid.type);
    APP_ERROR_CHECK(err_code);
    
    // OUR_JOB: Step 3.B, Set our service connection handle to default value. I.e. an invalid handle since we are not yet in a connection.
    p_our_service->conn_handle = BLE_CONN_HANDLE_INVALID;

	// STEP 4: Add our service
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &service_uuid, &p_our_service->service_handle);
    APP_ERROR_CHECK(err_code);

    our_char_add(p_our_service);
    our_char_bp_add(p_our_service);
    // Print messages to Segger Real Time Terminal
    // UNCOMMENT THE FOUR LINES BELOW AFTER INITIALIZING THE SERVICE OR THE EXAMPLE WILL NOT COMPILE.
//    SEGGER_RTT_WriteString(0, "Executing our_service_init().\n"); // Print message to RTT to the application flow
//    SEGGER_RTT_printf(0, "Service UUID: 0x%#04x\n", service_uuid.uuid); // Print service UUID should match definition BLE_UUID_OUR_SERVICE
//    SEGGER_RTT_printf(0, "Service UUID type: 0x%#02x\n", service_uuid.type); // Print UUID type. Should match BLE_UUID_TYPE_VENDOR_BEGIN. Search for BLE_UUID_TYPES in ble_types.h for more info
//    SEGGER_RTT_printf(0, "Service handle: 0x%#04x\n", p_our_service->service_handle); // Print out the service handle. Should match service handle shown in MCP under Attribute values
}

void our_temperature_characteristic_update(ble_os_t *p_our_service, int32_t *temperature_value)
{
// OUR_JOB: Step 3.E, Update characteristic value
    if (p_our_service->conn_handle != BLE_CONN_HANDLE_INVALID)
    {
	uint16_t               len = 4;
	ble_gatts_hvx_params_t hvx_params;
	memset(&hvx_params, 0, sizeof(hvx_params));

	hvx_params.handle = p_our_service->char_handles.value_handle;
	hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
	hvx_params.offset = 0;
	hvx_params.p_len  = &len;
	hvx_params.p_data = (uint8_t*)temperature_value;  

	sd_ble_gatts_hvx(p_our_service->conn_handle, &hvx_params);
    }    
}
void our_bp_characteristic_update(ble_os_t *p_our_service, int32_t *bp_value)
{
// OUR_JOB: Step 3.E, Update characteristic value
    if (p_our_service->conn_handle != BLE_CONN_HANDLE_INVALID)
    {
	uint16_t               len = 4;
	ble_gatts_hvx_params_t hvx_params;
	memset(&hvx_params, 0, sizeof(hvx_params));

	hvx_params.handle = p_our_service->char_bp_handles.value_handle;
	hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
	hvx_params.offset = 0;
	hvx_params.p_len  = &len;
	hvx_params.p_data = (uint8_t*)bp_value;  

	sd_ble_gatts_hvx(p_our_service->conn_handle, &hvx_params);
    }    
}

3. our_service.h: Header for custom service and characteristics:

5633.our_service.h

Thanks again, 

Paarth