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Can't enable DLE

Hi

For a project I want to send acceleration data via BLE 4.2 (with DLE). An acceleration packet consists of 81 values (24 bits each, total 243 bytes). My goal is to send 18 packets (1458 acceleration packets or 4374 bytes). After all packets have been sent, the connection to the smartphone (Samsung Galaxy A3 2017 Edition) is terminated and new 1458 acceleration packets are recorded. After that, an RTC activates sleep mode for 1 minute. After this minute the nRF should begin advertising and reconnecting to the smartphone.
The following figure illustrates the problem:

 

I have used this tutorial as a basis. With this tutorial I can only send 20 bytes at once.

 

Question 1:

Why can't I send more than 20 bytes? Even if I set maximum length to 27, only 20 bytes will be sent:

 

attr_char_value.max_len     = 27;

 

According to this thread you can enable DLE by using the function nrf_ble_gatt_data_length_set(). For the implementation of DLE I used the example ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput. The main.c contains the function data_len_set(). In it the DLE is enabled. Since there is no connection yet, BLE_CONN_HANDLE_INVALID is given as parameter:

 

void data_len_set(uint8_t value)
{
    ret_code_t err_code;
    err_code = nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, value);
    APP_ERROR_CHECK(err_code);

    m_test_params.data_len = value;
}

In the example, the two macros NRF_SDH_BLE_GAP_EVENT_LENGTH and NRF_SDH_BLE_GATT_MAX_MTU_SIZE are initialized as follows (sdk_config.h):

// <o> NRF_SDH_BLE_GAP_EVENT_LENGTH - GAP event length. 
// <i> The time set aside for this connection on every connection interval in 1.25 ms units.

#ifndef NRF_SDH_BLE_GAP_EVENT_LENGTH
#define NRF_SDH_BLE_GAP_EVENT_LENGTH 400
#endif

// <o> NRF_SDH_BLE_GATT_MAX_MTU_SIZE - Static maximum MTU size. 
#ifndef NRF_SDH_BLE_GATT_MAX_MTU_SIZE
#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 247
#endif

In the example of the tutorial I have adapted the sdk_config.h and main.c as mentioned above.

/**
 * 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 "our_service.h"

#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 "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 "our_service.h"


#define DEVICE_NAME                     "OurCharacteristic"                       /**< 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               (uint16_t)(MSEC_TO_UNITS(7.5, UNIT_1_25_MS))    /**< Minimum acceptable connection interval, in 1.25 ms units. */
//#define MAX_CONN_INTERVAL               (uint16_t)(MSEC_TO_UNITS(500, UNIT_1_25_MS))    /**< Maximum acceptable connection interval, in 1.25 ms units. */
//#define CONN_SUP_TIMEOUT                (uint16_t)(MSEC_TO_UNITS(4000,  UNIT_10_MS))    /**< Connection supervisory timeout (4 seconds). */
//#define SLAVE_LATENCY                   0                                               /**< Slave latency. */

#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 ACC_DATA 4374
static uint8_t acc_data_all[ACC_DATA];
static uint8_t acc_data[243];

static volatile bool disconnected = false;

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. */

void data_len_set(void);

// FROM_SERVICE_TUTORIAL: Declare a service structure for our application
ble_os_t m_our_service;


// OUR_JOB: Step 3.G, Declare an app_timer id variable and define our timer interval and define a timer interval
APP_TIMER_DEF(m_our_char_timer_id);
#define OUR_CHAR_TIMER_INTERVAL APP_TIMER_TICKS(1000) //1000 ms intervals



// Use UUIDs for service(s) used in your application.
static ble_uuid_t m_adv_uuids[] =                                               /**< Universally unique service identifiers. */
{
    {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);
}

void load_next_acc_value(uint16_t sp){
	static int i;
	sp = sp - 1;
	for(i = 0 ; i < 243 ; i++){
		acc_data[i] = acc_data_all[(sp*243) + i];
	}
}

// ALREADY_DONE_FOR_YOU: This is a timer event handler
static void timer_timeout_handler(void * p_context)
{
    // OUR_JOB: Step 3.F, Update temperature and characteristic value.
		int32_t temperature = 0;      //Declare a variable holding temperature value
                static int32_t previous_temperature=0;      //Declare a variable to store current temperature until next measurement. 

		sd_temp_get(&temperature);    //Get temperature
                

                // Check if current temperature is different from last temperature
                if(temperature != previous_temperature)
                    {
                      // If new temperature then send notification
                      our_temperature_characteristic_update(&m_our_service, &temperature);
                    }
                
                // Save current temperature until next measurement
                previous_temperature = temperature;
		nrf_gpio_pin_toggle(LED_4);
}



/**@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 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);


    // OUR_JOB: Step 3.H, Initiate our timer
    app_timer_create(&m_our_char_timer_id, APP_TIMER_MODE_REPEATED, timer_timeout_handler);

}


/**@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 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)
{

	
		uint32_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);

    //FROM_SERVICE_TUTORIAL: 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)
{

    // OUR_JOB: Step 3.I, Start our timer
    //app_timer_start(m_our_char_timer_id, OUR_CHAR_TIMER_INTERVAL, NULL);
    
    //To update temperature only when in a connection then don't call app_timer_start() here, but in ble_event_handler()
}


/**@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;
		static uint16_t total_send_packs = 0;
		static int i = 0;
		static uint8_t test_array[6];

    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);

            //When connected; start our timer to start regular temperature measurements
            app_timer_start(m_our_char_timer_id, OUR_CHAR_TIMER_INTERVAL, NULL);
            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;
				
				case BLE_GATTS_EVT_HVN_TX_COMPLETE:
						total_send_packs++;
						if(total_send_packs > 18) {
							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);
							total_send_packs = 0;
							disconnected = true;			
							//data_len_set();							
						}
						else { 
							// Preparing next Data
							//load_next_acc_value(total_send_packs);
							uint8_t test_array[NRF_SDH_BLE_GATT_MAX_MTU_SIZE];
							for ( i = 0 ; i < NRF_SDH_BLE_GATT_MAX_MTU_SIZE ; i++){
								test_array[i] = i;
							}
							// Sending next Data
							if (m_our_service.conn_handle != BLE_CONN_HANDLE_INVALID)
							{
									uint16_t               len = NRF_SDH_BLE_GATT_MAX_MTU_SIZE;
									ble_gatts_hvx_params_t hvx_params;
									memset(&hvx_params, 0, sizeof(hvx_params));

									hvx_params.handle = m_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*)test_array;  

									sd_ble_gatts_hvx(m_our_service.conn_handle, &hvx_params);
							}
						}
						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);

    //OUR_JOB: Step 3.C Set up a BLE event observer to call ble_our_service_on_ble_evt() to do housekeeping of ble connections related to our service and characteristics.
    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;

	
		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);
}


/**@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);
    }
}

void make_test_array(void){
	int i, k = 0,j = 0;
	while (k < ACC_DATA/243){
		for ( i = 243*k ; i < (243*k + 243) ; i++){
			acc_data_all[i] = j;
			if (j < 242){
				j++;
			}
			else {
				j = 0;
			}
		}
		k++;
	}
}

void data_len_set(void)
{
		static uint8_t value = NRF_SDH_BLE_GATT_MAX_MTU_SIZE;
    ret_code_t err_code;
    err_code = nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, value);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for application main entry.
 */
int main(void)
{
    bool erase_bonds;

    // Initialize.
		make_test_array();
    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("OurCharacteristics tutorial started.");
    application_timers_start();
		data_len_set();
    advertising_start(erase_bonds);
    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}


/**
 * @}
 */

In my code, data_len_set() is called before advertising_start(). As soon as I call data_len_set(), there is no advertising anymore.

Question 2:

Why is there no advertising anymore? Have I set a parameter somewhere wrong, which causes a problem with the SoftDevice?

My Setup:

nrf52832 dk

sdk V15.0

SoftDevice s132

Parents
  • Hi,

    Why can't I send more than 20 bytes? Even if I set maximum length to 27, only 20 bytes will be sent:

    Both sides of the link need to support long ATT MTU. It could be that the Galaxy A3 does not support long ATT MTU, and you will then be restricted to 20 bytes. A sniffer log with nRFSniffer v2 could show us exactly what is happening on-air.

    The main.c contains the function data_len_set(). In it the DLE is enabled.

    You don't need to call data_len_set(). Just set NRF_SDH_BLE_GAP_DATA_LENGTH in sdk_config.h to the value you want. The GATT module will handle the DLE negotiation with the other device.

    Why is there no advertising anymore?

    You are probably running in the error-handler(APP_ERROR_CHECK). Run a debug session in your IDE(e.g. segger embedded studio) to see where you get an error.

  • Hello Sigurd

    Thank you for your answer. Like you suggested i deletet data_len_set() from my code.

    Hence i changed the connection intervalls:

    #define MIN_CONN_INTERVAL               (uint16_t)(MSEC_TO_UNITS(7.5, UNIT_1_25_MS))
    #define MAX_CONN_INTERVAL               (uint16_t)(MSEC_TO_UNITS(500, UNIT_1_25_MS))
    #define CONN_SUP_TIMEOUT                (uint16_t)(MSEC_TO_UNITS(4000,  UNIT_10_MS))
    #define SLAVE_LATENCY                   0                                       

    1. Try

    For a first try i set 

    NRF_SDH_BLE_GAP_DATA_LENGTH = 27

    Hence i initialized "test_array" to:

    static uint8_t test_array[NRF_SDH_BLE_GAP_DATA_LENGTH];
    ...
    void short_arary(void){
      int i = 0; 
      for ( i = 0 ; i < NRF_SDH_BLE_GAP_DATA_LENGTH ; i++){ 
        test_array[i] = i; 
      } 
    }

    therefore test_array should be:

    test_array = {0, 1, 2, 3, ... , 26}

    i sniffed the BLE packages with cysmart 1.3 (Dongle: CY5677), nRF Connect (Android App running on my Samsung Galaxy A3 2017 Edition) and nRFSniffer v2 (nRF52840dk). 

    What i get from cysmart 1.3, nRF Connect and nRFSniffer v2 is (for one BLE package):

    test_arras = [00:01:02:03:04:05:06:07:08:09:0A:0B:0C:0D:0E:0F:10:11:12:13]

    nRFSniffer v2 output:

    ble_packages_27..pcapng

    cysmart 1.3 output:

    Question 1:

    Why do i only receive 20 and not 27 package?

    2. Try

    For a second try i changed 

    NRF_SDH_BLE_GAP_DATA_LENGTH = 27

    to

    NRF_SDH_BLE_GAP_DATA_LENGTH = 45

    my smartphone couldn't connect. 

    nRFSniffer v2 output:

    1754.ble_packages_45.pcapng

    cysmart 1.3 output:

     

Reply
  • Hello Sigurd

    Thank you for your answer. Like you suggested i deletet data_len_set() from my code.

    Hence i changed the connection intervalls:

    #define MIN_CONN_INTERVAL               (uint16_t)(MSEC_TO_UNITS(7.5, UNIT_1_25_MS))
    #define MAX_CONN_INTERVAL               (uint16_t)(MSEC_TO_UNITS(500, UNIT_1_25_MS))
    #define CONN_SUP_TIMEOUT                (uint16_t)(MSEC_TO_UNITS(4000,  UNIT_10_MS))
    #define SLAVE_LATENCY                   0                                       

    1. Try

    For a first try i set 

    NRF_SDH_BLE_GAP_DATA_LENGTH = 27

    Hence i initialized "test_array" to:

    static uint8_t test_array[NRF_SDH_BLE_GAP_DATA_LENGTH];
    ...
    void short_arary(void){
      int i = 0; 
      for ( i = 0 ; i < NRF_SDH_BLE_GAP_DATA_LENGTH ; i++){ 
        test_array[i] = i; 
      } 
    }

    therefore test_array should be:

    test_array = {0, 1, 2, 3, ... , 26}

    i sniffed the BLE packages with cysmart 1.3 (Dongle: CY5677), nRF Connect (Android App running on my Samsung Galaxy A3 2017 Edition) and nRFSniffer v2 (nRF52840dk). 

    What i get from cysmart 1.3, nRF Connect and nRFSniffer v2 is (for one BLE package):

    test_arras = [00:01:02:03:04:05:06:07:08:09:0A:0B:0C:0D:0E:0F:10:11:12:13]

    nRFSniffer v2 output:

    ble_packages_27..pcapng

    cysmart 1.3 output:

    Question 1:

    Why do i only receive 20 and not 27 package?

    2. Try

    For a second try i changed 

    NRF_SDH_BLE_GAP_DATA_LENGTH = 27

    to

    NRF_SDH_BLE_GAP_DATA_LENGTH = 45

    my smartphone couldn't connect. 

    nRFSniffer v2 output:

    1754.ble_packages_45.pcapng

    cysmart 1.3 output:

     

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