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Using ble_nus_data_send() in multiple peripherals example

Hi,

I am using NRF 52832 S132 sdk 15.2.0.

I am working with example project <install folder>\examples\ble-peripheral\experimental\ble-app_multiperipheral.

I added NUS to this project and is working properly. I want to send a message from NRF board (flashed with ble_app_multiperipheral example) to android device(Nordic Uart). After connecting with one cellphone it was working fine. But I want to send to multiple centrals (Android app Nordic UART). But when I tried to send to multiple centrals I got this error NRF_ERROR_RESOURCES. The below given is my main.c.

I am sending message in every one second using apptimer

I made changes in ble_evt_handler()

Please see send_message() function

/**
 * Copyright (c) 2015 - 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.
 *
 */

/**
 * @brief Multiperipheral Sample Application main file.
 *
 * This file contains the source code for a sample server application with multiple peripheral connections using the LED Button service.
 */

#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "boards.h"
#include "app_error.h"
#include "ble.h"
#include "ble_err.h"
#include "ble_hci.h"
#include "ble_srv_common.h"
#include "ble_advdata.h"
#include "ble_conn_params.h"
#include "ble_conn_state.h"
#include "nrf_sdh.h"
#include "nrf_sdh_ble.h"
#include "app_timer.h"
#include "app_button.h"
#include "ble_lbs.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_qwr.h"
#include "nrf_pwr_mgmt.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"


#define DEVICE_NAME                     "Nordic_Blinky"                         /**< Name of device. Will be included in the advertising data. */

#define APP_BLE_CONN_CFG_TAG            1                                       /**< A tag identifying the SoftDevice BLE configuration. */
#define LINK_TOTAL                      NRF_SDH_BLE_PERIPHERAL_LINK_COUNT + \
                                        NRF_SDH_BLE_CENTRAL_LINK_COUNT

#define ADVERTISING_LED                 BSP_BOARD_LED_0                         /**< Is on when device is advertising. */
#define CONNECTED_LED                   BSP_BOARD_LED_1                         /**< Is on when device has connected. */
#define LEDBUTTON_LED                   BSP_BOARD_LED_2                         /**< LED to be toggled with the help of the LED Button Service. */
#define LEDBUTTON_BUTTON                BSP_BUTTON_0                            /**< Button that will trigger the notification event with the LED Button Service */

#define APP_ADV_INTERVAL                64                                      /**< The advertising interval (in units of 0.625 ms; this value corresponds to 40 ms). */
#define APP_ADV_DURATION                BLE_GAP_ADV_TIMEOUT_GENERAL_UNLIMITED   /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)        /**< Minimum acceptable connection interval (0.5 seconds). */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(400, UNIT_1_25_MS)        /**< Maximum acceptable connection interval (1 second). */
#define SLAVE_LATENCY                   0                                       /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)         /**< Connection supervisory time-out (4 seconds). */

#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(20000)                  /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (15 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(5000)                   /**< Time between each call to sd_ble_gap_conn_param_update after the first call (5 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                       /**< Number of attempts before giving up the connection parameter negotiation. */

#define BUTTON_DETECTION_DELAY          APP_TIMER_TICKS(50)                     /**< Delay from a GPIOTE event until a button is reported as pushed (in number of timer ticks). */
#define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN                  /**< UUID type for the Nordic UART Service (vendor specific). */

#define DEAD_BEEF                       0xDEADBEEF                              /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */

#define UART_TX_BUF_SIZE                256                                         /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE                256                                         /**< UART RX buffer size. */

BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */

#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif

/**@brief   Priority of the application BLE event handler.
 * @note    You shouldn't need to modify this value.
 */
#define APP_BLE_OBSERVER_PRIO    3

static uint8_t m_adv_handle = BLE_GAP_ADV_SET_HANDLE_NOT_SET;                   /**< Advertising handle used to identify an advertising set. */
static uint8_t m_enc_advdata[BLE_GAP_ADV_SET_DATA_SIZE_MAX];                    /**< Buffer for storing an encoded advertising set. */
static uint8_t m_enc_scan_response_data[BLE_GAP_ADV_SET_DATA_SIZE_MAX];         /**< Buffer for storing an encoded scan data. */
static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
//static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_ALL;
static uint16_t   m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - 3;            /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */
#define APP_TIMER_PRESCALER             15    // Value of the RTC1 PRESCALER register.
#define APP_TIMER_OP_QUEUE_SIZE         3     // Size of timer operation queues.
APP_TIMER_DEF(tx_timer);                      //defining timer
#define NOTIFICATION_INTERVAL           APP_TIMER_TICKS(1000)  


/**@brief Struct that contains pointers to the encoded advertising data. */
static ble_gap_adv_data_t m_adv_data =
{
    .adv_data =
    {
        .p_data = m_enc_advdata,
        .len    = BLE_GAP_ADV_SET_DATA_SIZE_MAX
    },
    .scan_rsp_data =
    {
        .p_data = m_enc_scan_response_data,
        .len    = BLE_GAP_ADV_SET_DATA_SIZE_MAX

    }
};


BLE_LBS_DEF(m_lbs);                                                             /**< LED Button Service instance. */
NRF_BLE_GATT_DEF(m_gatt);                                                       /**< GATT module instance. */
NRF_BLE_QWRS_DEF(m_qwr, NRF_SDH_BLE_TOTAL_LINK_COUNT);                          /**< Context for the Queued Write module.*/

/**@brief Function for assert macro callback.
 *
 * @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] p_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);
}

//-----send message------//

static void send_message(void * p_context)
{
    ble_conn_state_conn_handle_list_t conn_handles = ble_conn_state_periph_handles();
    
    uint32_t       err_code;
    uint8_t data_array[2] = {'A', '\r'};
    uint16_t length = 1;
    NRF_LOG_DEBUG("Ready to send data over BLE NUS");
    NRF_LOG_HEXDUMP_DEBUG(data_array, length);

    do
    {
        
        for (uint8_t i = 0; i < conn_handles.len; i++)  //--this does not work
        {
            m_conn_handle = conn_handles.conn_handles[i];
            printf("\r\nconnection handle length: %d", conn_handles.conn_handles[i]);
            err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
        }
        //err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);-- This works
        printf("\r\nerror code: %d", err_code);
        if ((err_code != NRF_ERROR_INVALID_STATE) &&
            (err_code != NRF_ERROR_RESOURCES) &&
            (err_code != NRF_ERROR_NOT_FOUND))
        {
            APP_ERROR_CHECK(err_code);
        }
    } while (err_code == NRF_ERROR_RESOURCES);
    if(err_code == NRF_SUCCESS)
    {
      printf("\r\n message sent\r\n");
      bsp_board_led_invert(BSP_BOARD_LED_3);
    }

}
//-----send message------//


/**@brief Function for the LEDs initialization.
 *
 * @details Initializes all LEDs used by the application.
 */
static void leds_init(void)
{
    bsp_board_init(BSP_INIT_LEDS);
}


/**@brief Function for the Timer initialization.
 *
 * @details Initializes the timer module.
 */
static void timers_init(void)
{
    // Initialize timer module, making it use the scheduler
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
    err_code = app_timer_create(&tx_timer,
                                APP_TIMER_MODE_REPEATED,
                                send_message);
    
}


/**@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 handling the data from the Nordic UART Service.
 *
 * @details This function will process the data received from the Nordic UART BLE Service and send
 *          it to the UART module.
 *
 * @param[in] p_evt       Nordic UART Service event.
 */
/**@snippet [Handling the data received over BLE] */
static void nus_data_handler(ble_nus_evt_t * p_evt)
{
   
    
    if (p_evt->type == BLE_NUS_EVT_RX_DATA)
    {
        uint32_t err_code;


        NRF_LOG_DEBUG("Received data from BLE NUS. Writing data on UART.");
        NRF_LOG_HEXDUMP_DEBUG(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);

        for (uint32_t i = 0; i < p_evt->params.rx_data.length; i++)
        {
            do
            {
                err_code = app_uart_put(p_evt->params.rx_data.p_data[i]);
                bsp_board_led_invert(BSP_BOARD_LED_1);
                if ((err_code != NRF_SUCCESS) && (err_code != NRF_ERROR_BUSY))
                {
                    NRF_LOG_ERROR("Failed receiving NUS message. Error 0x%x. ", err_code);
                    APP_ERROR_CHECK(err_code);
                }
            } while (err_code == NRF_ERROR_BUSY);
        }
        if (p_evt->params.rx_data.p_data[p_evt->params.rx_data.length - 1] == '\r')
        {
            while (app_uart_put('\n') == NRF_ERROR_BUSY);
        }
    }

}
/**@snippet [Handling the data received over BLE] */


/**@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);

    err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for initializing the Advertising functionality.
 *
 * @details Encodes the required advertising data and passes it to the stack.
 *          Also builds a structure to be passed to the stack when starting advertising.
 */
static void advertising_init(void)
{
    ret_code_t           err_code;
    ble_advdata_t        advdata;
    ble_advdata_t        srdata;
    ble_gap_adv_params_t adv_params;


    ble_uuid_t adv_uuids[] = 
    {
      
      {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
    };

    // Build and set advertising data.
    memset(&advdata, 0, sizeof(advdata));

    advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    advdata.include_appearance = true;
    advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;


    memset(&srdata, 0, sizeof(srdata));
    srdata.uuids_complete.uuid_cnt = sizeof(adv_uuids) / sizeof(adv_uuids[0]);
    srdata.uuids_complete.p_uuids  = adv_uuids;

    err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_data.len);
    APP_ERROR_CHECK(err_code);

    err_code = ble_advdata_encode(&srdata, m_adv_data.scan_rsp_data.p_data, &m_adv_data.scan_rsp_data.len);
    APP_ERROR_CHECK(err_code);

    // Start advertising.
    memset(&adv_params, 0, sizeof(adv_params));
    adv_params.p_peer_addr   = NULL;
    adv_params.filter_policy = BLE_GAP_ADV_FP_ANY;
    adv_params.interval      = APP_ADV_INTERVAL;

    adv_params.properties.type = BLE_GAP_ADV_TYPE_CONNECTABLE_SCANNABLE_UNDIRECTED;
    adv_params.duration        = APP_ADV_DURATION;
    adv_params.primary_phy     = BLE_GAP_PHY_1MBPS;

    err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, &adv_params);
    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 write events to the LED characteristic.
 *
 * @param[in] p_lbs     Instance of LED Button Service to which the write applies.
 * @param[in] led_state Written/desired state of the LED.
 */
static void led_write_handler(uint16_t conn_handle, ble_lbs_t * p_lbs, uint8_t led_state)
{
    if (led_state)
    {
        bsp_board_led_on(LEDBUTTON_LED);
        NRF_LOG_INFO("Received LED ON from link 0x%x!", conn_handle);
    }
    else
    {
        bsp_board_led_off(LEDBUTTON_LED);
        NRF_LOG_INFO("Received LED OFF from link 0x%x!", conn_handle);
    }
}


/**@brief Function for initializing services that will be used by the application.
 */
static void services_init(void)
{
    ret_code_t         err_code;
    ble_nus_init_t     nus_init;
    //ble_lbs_init_t     init;
    nrf_ble_qwr_init_t qwr_init = {0};

    // Initialize Queued Write Module instances.
    qwr_init.error_handler = nrf_qwr_error_handler;

    for (uint32_t i = 0; i < LINK_TOTAL; i++)
    {
        err_code = nrf_ble_qwr_init(&m_qwr[i], &qwr_init);
        APP_ERROR_CHECK(err_code);
    }

    // Initialize LBS.
    //init.led_write_handler = led_write_handler;

    //err_code = ble_lbs_init(&m_lbs, &init);
    //APP_ERROR_CHECK(err_code);

    // Initialize NUS.
    memset(&nus_init, 0, sizeof(nus_init));

    nus_init.data_handler = nus_data_handler;

    err_code = ble_nus_init(&m_nus, &nus_init);
    APP_ERROR_CHECK(err_code);

    ble_conn_state_init();
}


/**@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             = true;
    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 advertising.
 */
static void advertising_start(void)
{
    ret_code_t err_code;
    
    err_code = sd_ble_gap_adv_start(m_adv_handle, APP_BLE_CONN_CFG_TAG);

    APP_ERROR_CHECK(err_code);
    bsp_board_led_on(ADVERTISING_LED);
}


/**@brief Function for handling the Connected event.
 *
 * @param[in] p_gap_evt GAP event received from the BLE stack.
 */
static void on_connected(const ble_gap_evt_t * const p_gap_evt)
{
    ret_code_t  err_code;
    uint32_t    periph_link_cnt = ble_conn_state_peripheral_conn_count(); // Number of peripheral links.

    NRF_LOG_INFO("Connection with link 0x%x established.", p_gap_evt->conn_handle);

    // Assign connection handle to available instance of QWR module.
    for (uint32_t i = 0; i < NRF_SDH_BLE_PERIPHERAL_LINK_COUNT; i++)
    {
        if (m_qwr[i].conn_handle == BLE_CONN_HANDLE_INVALID)
        {
            err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr[i], p_gap_evt->conn_handle);
            APP_ERROR_CHECK(err_code);
            break;
        }
    }

    err_code = app_button_enable();
    APP_ERROR_CHECK(err_code);

    // Update LEDs
    bsp_board_led_on(CONNECTED_LED);
    if (periph_link_cnt == NRF_SDH_BLE_PERIPHERAL_LINK_COUNT)
    {
        bsp_board_led_off(ADVERTISING_LED);
    }
    else
    {
        // Continue advertising. More connections can be established because the maximum link count has not been reached.
        advertising_start();
    }
}


/**@brief Function for handling the Disconnected event.
 *
 * @param[in] p_gap_evt GAP event received from the BLE stack.
 */
static void on_disconnected(ble_gap_evt_t const * const p_gap_evt)
{
    ret_code_t  err_code;
    uint32_t    periph_link_cnt = ble_conn_state_peripheral_conn_count(); // Number of peripheral links.

    NRF_LOG_INFO("Connection 0x%x has been disconnected. Reason: 0x%X",
                 p_gap_evt->conn_handle,
                 p_gap_evt->params.disconnected.reason);

    if (periph_link_cnt == 0)
    {
        bsp_board_led_off(CONNECTED_LED);
        err_code = app_button_disable();
        APP_ERROR_CHECK(err_code);
    }

    if (periph_link_cnt == (NRF_SDH_BLE_PERIPHERAL_LINK_COUNT - 1))
    {
        // Advertising is not running when all connections are taken, and must therefore be started.
        advertising_start();
    }
}


/**@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;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            on_connected(&p_ble_evt->evt.gap_evt);
            //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_DISCONNECTED:
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            on_disconnected(&p_ble_evt->evt.gap_evt);
            break;

        case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
            // Pairing not supported
            err_code = sd_ble_gap_sec_params_reply(p_ble_evt->evt.gap_evt.conn_handle,
                                                   BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP,
                                                   NULL,
                                                   NULL);
            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_GATTS_EVT_SYS_ATTR_MISSING:
            // No system attributes have been stored.
            err_code = sd_ble_gatts_sys_attr_set(p_ble_evt->evt.gap_evt.conn_handle, NULL, 0, 0);
            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 writing to the LED characteristic of all connected clients.
 *
 * @details Based on if the button is pressed or released, this function writes a high or low
 *          LED status to the server.
 *
 * @param[in] button_action The button action (press/release).
 *            Determines if the LEDs of the servers will be ON or OFF.
 *
 * @return If successful NRF_SUCCESS is returned. Otherwise, the error code from @ref ble_lbs_led_status_send.
 */
static uint32_t led_status_send_to_all(uint8_t button_action)
{
    ret_code_t                        err_code;
    ble_conn_state_conn_handle_list_t conn_handles = ble_conn_state_periph_handles();
    printf("\r\nLed send status function, connID:%d", conn_handles.len);

    for (uint8_t i = 0; i < conn_handles.len; i++)
    {
        err_code = ble_lbs_on_button_change(conn_handles.conn_handles[i], &m_lbs, button_action);

        if (err_code != NRF_SUCCESS &&
            err_code != BLE_ERROR_INVALID_CONN_HANDLE &&
            err_code != NRF_ERROR_INVALID_STATE &&
            err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING)
        {
            APP_ERROR_CHECK(err_code);
            NRF_LOG_DEBUG("Sent button change 0x%x on connection handle 0x%x.", button_action, conn_handles.conn_handles[i]);
        }
    }
    return NRF_SUCCESS;
}


/**@brief Function for handling events from the button handler module.
 *
 * @param[in] pin_no        The pin that the event applies to.
 * @param[in] button_action The button action (press/release).
 */
static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
    ret_code_t err_code;

    switch (pin_no)
    {
        case LEDBUTTON_BUTTON:
            err_code = led_status_send_to_all(button_action);
            if (err_code == NRF_SUCCESS)
            {
                NRF_LOG_INFO("Sent button state change to all connected centrals.");
            }
            break;

        default:
            APP_ERROR_HANDLER(pin_no);
            break;
    }
}


/**@brief   Function for handling app_uart events.
 *
 * @details This function will receive a single character from the app_uart module and append it to
 *          a string. The string will be be sent over BLE when the last character received was a
 *          'new line' '\n' (hex 0x0A) or if the string has reached the maximum data length.
 */
/**@snippet [Handling the data received over UART] */
void uart_event_handle(app_uart_evt_t * p_event)
{
    static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
    static uint8_t index = 0;
    uint32_t       err_code;

    switch (p_event->evt_type)
    {
        case APP_UART_DATA_READY:
            UNUSED_VARIABLE(app_uart_get(&data_array[index]));
            index++;

            if ((data_array[index - 1] == '\n') ||
                (data_array[index - 1] == '\r') ||
                (index >= m_ble_nus_max_data_len))
            {
                if (index > 1)
                {
                    NRF_LOG_DEBUG("Ready to send data over BLE NUS");
                    NRF_LOG_HEXDUMP_DEBUG(data_array, index);

                    do
                    {
                        uint16_t length = (uint16_t)index;
                        err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
                        if ((err_code != NRF_ERROR_INVALID_STATE) &&
                            (err_code != NRF_ERROR_RESOURCES) &&
                            (err_code != NRF_ERROR_NOT_FOUND))
                        {
                            APP_ERROR_CHECK(err_code);
                        }
                    } while (err_code == NRF_ERROR_RESOURCES);
                }

                index = 0;
            }
            break;

        case APP_UART_COMMUNICATION_ERROR:
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}
/**@snippet [Handling the data received over UART] */


/**@brief Function for initializing the button handler module.
 */
static void buttons_init(void)
{
    ret_code_t err_code;

    //The array must be static because a pointer to it will be saved in the button handler module.
    static app_button_cfg_t buttons[] =
    {
        {LEDBUTTON_BUTTON, false, BUTTON_PULL, button_event_handler}
    };

    err_code = app_button_init(buttons, ARRAY_SIZE(buttons),
                               BUTTON_DETECTION_DELAY);
    APP_ERROR_CHECK(err_code);
}


/**@snippet [Handling the data received over UART] */


/**@brief  Function for initializing the UART module.
 */
/**@snippet [UART Initialization] */
static void uart_init(void)
{
    uint32_t                     err_code;
    app_uart_comm_params_t const comm_params =
    {
        .rx_pin_no    = RX_PIN_NUMBER,
        .tx_pin_no    = TX_PIN_NUMBER,
        .rts_pin_no   = RTS_PIN_NUMBER,
        .cts_pin_no   = CTS_PIN_NUMBER,
        .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
        .use_parity   = false,
#if defined (UART_PRESENT)
        .baud_rate    = NRF_UART_BAUDRATE_115200
#else
        .baud_rate    = NRF_UARTE_BAUDRATE_115200
#endif
    };

    APP_UART_FIFO_INIT(&comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_event_handle,
                       APP_IRQ_PRIORITY_LOWEST,
                       err_code);
    //APP_ERROR_CHECK(err_code);
}
/**@snippet [UART Initialization] */


/**@brief Function for initializing the logging 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 application main entry.
 */
int main(void)
{
    // Initialize.
    log_init();
    uart_init();
    printf("\r\nUART started begin.\r\n");
    timers_init();
    leds_init();
    buttons_init();
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();


    // Start execution.
    NRF_LOG_INFO("Multiperipheral example started.");
    
    app_timer_start(tx_timer, NOTIFICATION_INTERVAL, NULL);
    advertising_start();
    bsp_board_led_invert(2);

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


/**
 * @}
 */

How can I add handles dynamically and send message to each centrals?

Parents
  • Hello,

    How many packets did you send before you get the NRF_ERROR_RESOURCES?

    This return means that the softdevice's internal buffer is full, and you need to wait for a TX_COMPLETE event before queuing more packets with ble_nus_data_send().

    There are quite a lot of DevZone tickets regarding this issue. Please check out e.g. this one.

    Best regards,

    Edvin

  • Hi Edvin,

    I went through most of those Devzone tickets. I want to send data to many central devices from a single peripheral. So I am bit confused about connection handles too.

    static void send_message(void * p_context)
    {
        ble_conn_state_conn_handle_list_t conn_handles = ble_conn_state_periph_handles();
        
        uint32_t       err_code;
        uint8_t data_array[2] = {'A', '\r'};
        uint16_t length = 1;
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        NRF_LOG_HEXDUMP_DEBUG(data_array, length);
    
        do
        {
            
            for (uint8_t i = 0; i < conn_handles.len; i++)  //--this does not work
            {
                m_conn_handle = conn_handles.conn_handles[i];
                printf("\r\nconnection handle length: %d", conn_handles.conn_handles[i]);
                err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
            }
            //err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle); //-- This works
            printf("\r\nerror code: %d", err_code);
            if ((err_code != NRF_ERROR_INVALID_STATE) &&
                (err_code != NRF_ERROR_RESOURCES) &&
                (err_code != NRF_ERROR_NOT_FOUND))
            {
                APP_ERROR_CHECK(err_code);
            }
        } while (err_code == NRF_ERROR_RESOURCES);
        if(err_code == NRF_SUCCESS)
        {
          printf("\r\n message sent\r\n");
          bsp_board_led_invert(BSP_BOARD_LED_3);
        }
    
    }
    

    In the above function I am sending data to my centrals. Just one character, but I have to send it to all my peripherals. Currently I can send it to last connected central. How can I assign handle to each central and transfer parallely. 

    I am trying to send messages based on this macro BLE_GATTS_EVT_HVN_TX_COMPLETE.

    Thank you.

Reply
  • Hi Edvin,

    I went through most of those Devzone tickets. I want to send data to many central devices from a single peripheral. So I am bit confused about connection handles too.

    static void send_message(void * p_context)
    {
        ble_conn_state_conn_handle_list_t conn_handles = ble_conn_state_periph_handles();
        
        uint32_t       err_code;
        uint8_t data_array[2] = {'A', '\r'};
        uint16_t length = 1;
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        NRF_LOG_HEXDUMP_DEBUG(data_array, length);
    
        do
        {
            
            for (uint8_t i = 0; i < conn_handles.len; i++)  //--this does not work
            {
                m_conn_handle = conn_handles.conn_handles[i];
                printf("\r\nconnection handle length: %d", conn_handles.conn_handles[i]);
                err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
            }
            //err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle); //-- This works
            printf("\r\nerror code: %d", err_code);
            if ((err_code != NRF_ERROR_INVALID_STATE) &&
                (err_code != NRF_ERROR_RESOURCES) &&
                (err_code != NRF_ERROR_NOT_FOUND))
            {
                APP_ERROR_CHECK(err_code);
            }
        } while (err_code == NRF_ERROR_RESOURCES);
        if(err_code == NRF_SUCCESS)
        {
          printf("\r\n message sent\r\n");
          bsp_board_led_invert(BSP_BOARD_LED_3);
        }
    
    }
    

    In the above function I am sending data to my centrals. Just one character, but I have to send it to all my peripherals. Currently I can send it to last connected central. How can I assign handle to each central and transfer parallely. 

    I am trying to send messages based on this macro BLE_GATTS_EVT_HVN_TX_COMPLETE.

    Thank you.

Children
  • Hello,

    If all ble_nus_data_send() returns NRF_SUCCESS, then you should be fine, and you don't need to worry about the BLE_GATTS_EVT_HVN_TX_COMPLETE events.

    BUT: You should check your err_code from ble_nus_data_send. If it returns NRF_ERROR_RESOURCES, it is correct that you shouldn't pass it to APP_ERROR_CHECK(err_code), but you still have to check it. 

    Your implementation will work, but it has some faulty behavior. 

    Let us say that you have space for 2 messages in your queue, and you are connected to 3 devices. The first two will return NRF_SUCCESS, while the last will return NRF_ERROR_RESOURCES. Now, err_code == NRF_ERROR_RESOURCES, and it will continue with conn_handle = 0 (the first), and try again. So you will restart the for-loop if and only if the last connected device returns NRF_ERROR_RESOURCES.

    You should remove the do-while loop. Instead, you should store the last successful transmission's conn_handle, and resume transmitting to the next conn_handle when you receive the TX_COMPLETE event:

    volatile uint8_t m_last_successful_conn_handle = 0;
    
    
    ble_evt_handler()
    {
        ...
            case BLE_GATTS_EVT_HVN_TX_COMPLETE:
            send_message()
            break;
    }
    
    void send_message()
    {
        for (uint8_t i=m_last_successful_conn_handle; i<conn_handles.len; i++)
        {
            err_code = ble_nus_data_send(...)
            if(err_code == NRF_SUCCESS)
            {
                m_last_successful_conn_handle++;
            }
            else if (err_code == NRF_ERROR_RESOURCES)
            {
                // Queue is full. Break the loop, and countinue with the m_last_successful_conn_handle after TX_COMPLETE
                break;
            }
        }
        if (m_last_successful_conn_hanlde == conn_hanldes.len)
        {
            m_last_successful_conn_handle = 0;
        }
    }

    Something like this (pseudo code)

    Best regards,

    Edvin

  • Hi Edvin,

    Thank you for the reply. I have to send message in every one second from peripheral. So I am using app timer to send message. So when connection is established  I am starting my apptimer.

    static void on_connected(const ble_gap_evt_t * const p_gap_evt)
    {
        ret_code_t  err_code;
        uint32_t    periph_link_cnt = ble_conn_state_peripheral_conn_count(); // Number of peripheral links.
        ble_conn_state_conn_handle_list_t conn_handles = ble_conn_state_periph_handles();
    
        NRF_LOG_INFO("Connection with link 0x%x established.", p_gap_evt->conn_handle);
        for (uint8_t i = 0; i < conn_handles.len; i++)  //--this does not work
          {
              m_conn_handle = conn_handles.conn_handles[i];
              printf("\r\nconnection handle length: %d", conn_handles.conn_handles[i]);
              
          }
    
        // Assign connection handle to available instance of QWR module.
        for (uint32_t i = 0; i < NRF_SDH_BLE_PERIPHERAL_LINK_COUNT; i++)
        {
            if (m_qwr[i].conn_handle == BLE_CONN_HANDLE_INVALID)
            {
                err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr[i], p_gap_evt->conn_handle);
                APP_ERROR_CHECK(err_code);
                break;
            }
        }
    
        err_code = app_button_enable();
        APP_ERROR_CHECK(err_code);
    
        // Update LEDs
        bsp_board_led_on(CONNECTED_LED);
        if (periph_link_cnt == NRF_SDH_BLE_PERIPHERAL_LINK_COUNT)
        {
            bsp_board_led_off(ADVERTISING_LED);
        }
        else
        {
            // Continue advertising. More connections can be established because the maximum link count has not been reached.
            advertising_start();
        }
        app_timer_start(tx_timer, NOTIFICATION_INTERVAL, NULL);
        
    }
    

    Above given is my on_connected function where I start my apptimer. Then I stop it in on_disconnected function, when peripheral link count is 0.

    static void send_message(void * p_context)
    {
        uint32_t       err_code = 0;
        ble_evt_t const * p_ble_evt;
        uint8_t data_array[15] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', '\r'};
        uint16_t length = 8;
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        NRF_LOG_HEXDUMP_DEBUG(data_array, length);
        uint32_t connection_handle_len = 0;
        connection_handle_len = ble_conn_state_conn_count(); //conn_handles.len;
        printf("\r\n connection handle length: %d", connection_handle_len);
        if(transmission_complete == 0)
        {
    	err_code = ble_nus_data_send(&m_nus, data_array, &length, 0);
    	printf("\r\n Entering here only once");
        }
        
    
        if (connection_handle_len) 
        {
    	do 
    	{
    	    for(uint32_t i = 0; i < connection_handle_len; i++)
    	    {
    		
                    
    		        err_code = ble_nus_data_send(&m_nus, data_array, &length, i);
    		
                    printf("\r\n i: %d", i);	
                    printf("\r\nerror code: %d", err_code);	
    	    }
    	    
    	    if ((err_code != NRF_ERROR_INVALID_STATE) &&
    		(err_code != NRF_ERROR_RESOURCES) &&
    		(err_code != NRF_ERROR_NOT_FOUND))
    	    {
    		APP_ERROR_CHECK(err_code);
    	    }
    
    	} while (err_code == NRF_ERROR_RESOURCES);
    
    	if(err_code == NRF_SUCCESS)
    	{
    	  printf("\r\n message sent\r\n");
    	  bsp_board_led_invert(BSP_BOARD_LED_3);
    	}
        }
    }
    //-----send message------//
    

    The above given is my send message code. When I am connecting more than 2 device to the peripheral I am getting the following error.

    error code: 12290Logs dropped (1)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (1)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x50.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x10.
    <info> app: Connection with link 0x6 established.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x55.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Peer on connection 0x6 requested an ATT MTU of 247 bytes.
    Logs dropped (2)
    <debug> nrf_ble_gatt: Updating ATT MTU to 23 bytes (desired: 23) on connection 0x6.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x23.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Peer on connection 0x6 requested a data length of 251 bytes.
    Logs dropped (2)
    <debug> nrf_ble_gatt: Updating data length to 27 on connection 0x6.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x50.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x24.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Data length updated to 27 on connection 0x6.
    <debug> nrf_ble_gatt: max_rx_octets: 27
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_tx_octets: 27
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_rx_time: 2120
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_tx_time: 2120
    <debug> app: Ready to send data over BLE NUS
    Logs dropped (2)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (2)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x10.
    Logs dropped (1)
    <info> app: Connection with link 0x7 established.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x55.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Peer on connection 0x7 requested an ATT MTU of 247 bytes.
    Logs dropped (2)
    <debug> nrf_ble_gatt: Updating ATT MTU to 23 bytes (desired: 23) on connection 0x7.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x10.
    Logs dropped (1)
    <info> app: Connection with link 0x8 established.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x55.
    <debug> nrf_ble_gatt: Peer on connection 0x8 requested an ATT MTU of 247 bytes.
    Logs dropped (2)
    <debug> nrf_ble_gatt: Updating ATT MTU to 23 bytes (desired: 23) on connection 0x8.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x23.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Peer on connection 0x7 requested a data length of 251 bytes.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Updating data length to 27 on connection 0x7.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x23.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Peer on connection 0x8 requested a data length of 251 bytes.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Updating data length to 27 on connection 0x8.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x24.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Data length updated to 27 on connection 0x8.
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_rx_octets: 27
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_tx_octets: 27
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_rx_time: 2120
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_tx_time: 2120
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x24.
    Logs dropped (1)
    <debug> nrf_ble_gatt: Data length updated to 27 on connection 0x7.
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_rx_octets: 27
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_tx_octets: 27
    Logs dropped (1)
    <debug> nrf_ble_gatt: max_rx_time: 2120
    <debug> nrf_ble_gatt: max_tx_time: 2120
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x11.
    Logs dropped (1)
    <info> app: Connection 0x2 has been disconnected. Reason: 0x8
    Logs dropped (1)
    <debug> app: Ready to send data over BLE NUS
    Logs dropped (4)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (4)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    <debug> nrf_sdh_ble: BLE event: 0x11.
    Logs dropped (2)
    <info> app: Connection 0x0 has been disconnected. Reason: 0x8
    Logs dropped (2)
    <debug> nrf_sdh_ble: BLE event: 0x11.
    Logs dropped (2)
    <info> app: Connection 0x1 has been disconnected. Reason: 0x8
    Logs dropped (2)
    <debug> nrf_sdh_ble: BLE event: 0x50.
    Logs dropped (2)
    <debug> app: Ready to send data over BLE NUS
    Logs dropped (4)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (4)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    Logs dropped (2)
    <debug> nrf_sdh_ble: BLE event: 0x50.
    Logs dropped (1)
    <debug> nrf_sdh_ble: BLE event: 0x50.
    <debug> app: Ready to send data over BLE NUS
    Logs dropped (5)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (5)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    <debug> nrf_sdh_ble: BLE event: 0x11.
    Logs dropped (4)
    <info> app: Connection 0x3 has been disconnected. Reason: 0x8
    <debug> app: Ready to send data over BLE NUS
    Logs dropped (4)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (4)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    Logs dropped (2)
    <debug> nrf_sdh_ble: BLE event: 0x11.
    Logs dropped (2)
    <info> app: Connection 0x4 has been disconnected. Reason: 0x8
    Logs dropped (2)
    <debug> nrf_sdh_ble: BLE event: 0x11.
    Logs dropped (2)
    <info> app: Connection 0x5 has been disconnected. Reason: 0x8
    Logs dropped (2)
    <debug> app: Ready to send data over BLE NUS
    Logs dropped (4)
    <debug> app:  41 42 43 44 45 46 47 48|ABCDEFGH
    Logs dropped (4)
    <debug> app:  49 4A 4B 4C 4D 0D 00   |IJKLM.. 
    <error> app: Fatal error
    

    Is this error coming because the buffer is full at the time? Is it like I can not send 15 bytes of data to 3 centrals at a time. I tried like the way you mentioned. Using BLE_GATTS_EVT_HVN_TX_COMPLETE. I set one flag when this event comes. And I will check that flag and will send message when it is high. In that scenario I get NRF_ERROR_RESOURCES.

    //-----send message------//
    
    static void send_message(void * p_context)
    {
        uint32_t       err_code = 0;
        ble_evt_t const * p_ble_evt;
    
        uint8_t data_array[15] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', '\r'};
        uint16_t length = 15;
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        NRF_LOG_HEXDUMP_DEBUG(data_array, length);
        uint32_t connection_handle_len = 0;
        connection_handle_len = ble_conn_state_conn_count(); //conn_handles.len;
        printf("\r\n connection handle length: %d", connection_handle_len);
        if(transmission_complete == 0)
        {
    	err_code = ble_nus_data_send(&m_nus, data_array, &length, 0);
    	printf("\r\n Entering here only once");
        }
        
    
        if (connection_handle_len) 
        {
    	do 
    	{
    	    for(uint32_t i = 0; i < connection_handle_len; i++)
    	    {
    		
                    if(transmission_complete == 1)
    		{
    		    err_code = ble_nus_data_send(&m_nus, data_array, &length, i);
                        printf("\r\n Entering here all the time");
    		    transmission_complete = 0;
    
    		}
    		
                    printf("\r\n i: %d", i);	
                    printf("\r\nerror code: %d", err_code);	
    	    }
    	    
    	    if ((err_code != NRF_ERROR_INVALID_STATE) &&
    		(err_code != NRF_ERROR_RESOURCES) &&
    		(err_code != NRF_ERROR_NOT_FOUND))
    	    {
    		APP_ERROR_CHECK(err_code);
    	    }
    
    	} while (err_code == NRF_ERROR_RESOURCES);
    
    	if(err_code == NRF_SUCCESS)
    	{
    	  printf("\r\n message sent\r\n");
    	  bsp_board_led_invert(BSP_BOARD_LED_3);
    	}
        }
    }
    //-----send message------//
    

    Should I increase NRF_SDH_BLE_GAP_EVENT_LENGTH or  NRF_SDH_BLE_GATT_MAX_MTU_SIZE

  • You can increase NRF_SDH_BLE_GATT_MAX_MTU_SIZE, but you may still encounter this error, so you have to handle it correctly.

    Your implementation in the last snippet will probably work, as far as I can tell, but it is not power efficient. What is your connection interval? In this implementation:

    do
    {
        err_code = ble_nus_data_send();
    }while (err_code == NRF_ERROR_RESOURCES)

    It will keep spinning through ble_nus_data_send() until it gets a TX_COMPLETE (BLE_GATTS_EVT_HVN_TX_COMPLETE) event. This will not happen until a packet is delivered, earliest the next connection event (which occurs each connection interval). 

    Therefore, when you receive an NRF_ERROR_RESOURCES from ble_nus_data_send() you should break, so that the chip can go to sleep until the next connection event, and then resume sending messages. 

    What is your log output from your last snippet? Were you able to send to all devices? And what is your connection interval (MIN and MAX) on your central(s) and peripheral(s)?

  • Hi Edvin,

    Sorry for the delay in reply.

    My connection intervals in peripheral:

    #define MIN_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)
    #define MAX_CONN_INTERVAL               MSEC_TO_UNITS(400, UNIT_1_25_MS) 

    I am using ble_app_uart_c as my central device. So there is no connection interval set.

    I changed my code a little bit. Now I am sending data based on acknowledgement from each central. Above snippets did not work.

  • The connection interval on the central is set in sdk_config.h. It is called NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL and NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL.

    Did you try to implement the break and resume on the TX_COMPLETE event?

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