Handling data two times from one of the peripherals

[Seyma Tutuncu]

Hello,

I have been struggling with multilink uart example for a while. I have done 3 peripherals and one central communication but still I have some problems. I am using SDK 14.2.0 and 4 EYSHSNZWZ modules from Taiyo Yuden.

Central side sends data to peripherals that I send from computer via RS232 correctly, however when I send data from peripherals continuously, one of the peripherals sends the data two times. I think it is because of the central code, not the peripherals because I use same code for peripherals. I think that central shows the data two times. For example for handle 2, peripheral sends 5 bytes but central shows 10 bytes. For the other connection handles, central shows what is send from peripherals.

The main code for central is here:

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 */
/**
 * @brief BLE LED Button Service central and client application main file.
 *
 * This example can be a central for up to 8 peripherals.
 * The peripheral is called ble_app_blinky and can be found in the ble_peripheral
 * folder.
 */

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "nordic_common.h"
#include "app_error.h"
#include "app_uart.h"
#include "nrf_sdh.h"
#include "nrf_sdh_ble.h"
#include "app_timer.h"
#include "app_util.h"
#include "bsp_btn_ble.h"
#include "ble.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "ble_db_discovery.h"
#include "ble_conn_state.h"
#include "ble_nus_c.h"
#include "nrf_ble_gatt.h"
#include "nrf_delay.h"

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


#define APP_BLE_CONN_CFG_TAG      1                                     /**< A tag that refers to the BLE stack configuration we set with @ref sd_ble_cfg_set. Default tag is @ref APP_BLE_CONN_CFG_TAG. */
#define APP_BLE_OBSERVER_PRIO     3                                     /**< Application's BLE observer priority. You shouldn't need to modify this value. */

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

#define CENTRAL_SCANNING_LED      BSP_BOARD_LED_0
#define CENTRAL_CONNECTED_LED     BSP_BOARD_LED_1
#define LEDBUTTON_LED             BSP_BOARD_LED_2                       /**< LED to indicate a change of state of the the Button characteristic on the peer. */

#define LEDBUTTON_BUTTON          BSP_BUTTON_0                          /**< Button that will write to the LED characteristic of the peer. */
#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 SCAN_INTERVAL             0x00A0                                /**< Determines scan interval in units of 0.625 millisecond. */
#define SCAN_WINDOW               0x0050                                /**< Determines scan window in units of 0.625 millisecond. */
#define SCAN_TIMEOUT              0x0000                                /**< Timout when scanning. 0x0000 disables timeout. */

#define MIN_CONNECTION_INTERVAL   MSEC_TO_UNITS(7.5, UNIT_1_25_MS)      /**< Determines minimum connection interval in milliseconds. */
#define MAX_CONNECTION_INTERVAL   MSEC_TO_UNITS(30, UNIT_1_25_MS)       /**< Determines maximum connection interval in milliseconds. */
#define SLAVE_LATENCY             0                                     /**< Determines slave latency in terms of connection events. */
#define SUPERVISION_TIMEOUT       MSEC_TO_UNITS(4000, UNIT_10_MS)       /**< Determines supervision time-out in units of 10 milliseconds. */

#define UUID16_SIZE             2                                       /**< Size of 16 bit UUID */
#define UUID32_SIZE             4                                       /**< Size of 32 bit UUID */
#define UUID128_SIZE            16                                      /**< Size of 128 bit UUID */

#define ECHOBACK_BLE_UART_DATA  1                                       /**< Echo the UART data that is received over the Nordic UART Service back to the sender. */

NRF_BLE_GATT_DEF(m_gatt);                                               /**< GATT module instance. */
BLE_NUS_C_ARRAY_DEF(m_ble_nus_c, NRF_SDH_BLE_CENTRAL_LINK_COUNT);                                             /**< BLE NUS service client instance. */
BLE_DB_DISCOVERY_DEF(m_db_disc);  /**< Database discovery module instances. */

static char const m_target_periph_name[] = "Nordic_Blinky";             /**< Name of the device we try to connect to. This name is searched for in the scan report data*/
static uint16_t m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - OPCODE_LENGTH - HANDLE_LENGTH; /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */


/**@brief Scan parameters requested for scanning and connection. */
static ble_gap_scan_params_t const m_scan_params =
{
    .active   = 0,
    .interval = SCAN_INTERVAL,
    .window   = SCAN_WINDOW,
    .timeout  = SCAN_TIMEOUT,
    #if (NRF_SD_BLE_API_VERSION <= 2)
        .selective   = 0,
        .p_whitelist = NULL,
    #endif
    #if (NRF_SD_BLE_API_VERSION >= 3)
        .use_whitelist  = 0,
        .adv_dir_report = 0,
    #endif
};

/**@brief Connection parameters requested for connection. */
static ble_gap_conn_params_t const m_connection_param =
{
    (uint16_t)MIN_CONNECTION_INTERVAL,
    (uint16_t)MAX_CONNECTION_INTERVAL,
    (uint16_t)SLAVE_LATENCY,
    (uint16_t)SUPERVISION_TIMEOUT
};


/**@brief Function to handle 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] 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(0xDEADBEEF, line_num, p_file_name);
}


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


/**
 * @brief Parses advertisement data, providing length and location of the field in case
 *        matching data is found.
 *
 * @param[in]  type       Type of data to be looked for in advertisement data.
 * @param[in]  p_advdata  Advertisement report length and pointer to report.
 * @param[out] p_typedata If data type requested is found in the data report, type data length and
 *                        pointer to data will be populated here.
 *
 * @retval NRF_SUCCESS if the data type is found in the report.
 * @retval NRF_ERROR_NOT_FOUND if the data type could not be found.
 */
static uint32_t adv_report_parse(uint8_t type, uint8_array_t * p_advdata, uint8_array_t * p_typedata)
{
    uint32_t  index = 0;
    uint8_t * p_data;

    p_data = p_advdata->p_data;

    while (index < p_advdata->size)
    {
        uint8_t field_length = p_data[index];
        uint8_t field_type   = p_data[index + 1];

        if (field_type == type)
        {
            p_typedata->p_data = &p_data[index + 2];
            p_typedata->size   = field_length - 1;
            return NRF_SUCCESS;
        }
        index += field_length + 1;
    }
    return NRF_ERROR_NOT_FOUND;
}


/**@brief Function to start scanning. */
static void scan_start(void)
{
    ret_code_t ret;

    (void) sd_ble_gap_scan_stop();

    NRF_LOG_INFO("Start scanning for device name %s.", (uint32_t)m_target_periph_name);
    ret = sd_ble_gap_scan_start(&m_scan_params);
    APP_ERROR_CHECK(ret);

    ret = bsp_indication_set(BSP_INDICATE_SCANNING);
    APP_ERROR_CHECK(ret);
}



/**@brief Function for handling the advertising report BLE event.
 *
 * @param[in] p_ble_evt  Bluetooth stack event.
 */
static void on_adv_report(ble_evt_t const * p_ble_evt)
{
    uint32_t      err_code;
    uint8_array_t adv_data;
    uint8_array_t dev_name;
    bool          do_connect = false;

    // For readibility.
    ble_gap_evt_t  const * p_gap_evt  = &p_ble_evt->evt.gap_evt;
    ble_gap_addr_t const * peer_addr  = &p_gap_evt->params.adv_report.peer_addr;

    // Prepare advertisement report for parsing.
    adv_data.p_data = (uint8_t *)p_gap_evt->params.adv_report.data;
    adv_data.size   = p_gap_evt->params.adv_report.dlen;

    // Search for advertising names.
    bool found_name = false;
    err_code = adv_report_parse(BLE_GAP_AD_TYPE_COMPLETE_LOCAL_NAME,
                                &adv_data,
                                &dev_name);
    if (err_code != NRF_SUCCESS)
    {
        // Look for the short local name if it was not found as complete.
        err_code = adv_report_parse(BLE_GAP_AD_TYPE_SHORT_LOCAL_NAME, &adv_data, &dev_name);
        if (err_code != NRF_SUCCESS)
        {
            // If we can't parse the data, then exit.
            return;
        }
        else
        {
            found_name = true;
        }
    }
    else
    {
        found_name = true;
    }

    if (found_name)
    {
        if (strlen(m_target_periph_name) != 0)
        {
            if (memcmp(m_target_periph_name, dev_name.p_data, dev_name.size) == 0)
            {
                do_connect = true;
            }
        }
    }

    if (do_connect)
    {
        // Initiate connection.
        err_code = sd_ble_gap_connect(peer_addr, &m_scan_params, &m_connection_param, APP_BLE_CONN_CFG_TAG);
        if (err_code != NRF_SUCCESS)
        {
            NRF_LOG_ERROR("Connection Request Failed, reason %d", err_code);
        }
    }
}


/**@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;

    // For readability.
    ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;

    switch (p_ble_evt->header.evt_id)
    {
        // Upon connection, check which peripheral has connected, initiate DB
        // discovery, update LEDs status and resume scanning if necessary.
        case BLE_GAP_EVT_CONNECTED:
        {
            NRF_LOG_INFO("Connection 0x%x established, starting DB discovery.",
                         p_gap_evt->conn_handle);

            APP_ERROR_CHECK_BOOL(p_gap_evt->conn_handle < NRF_SDH_BLE_CENTRAL_LINK_COUNT);

            //err_code = ble_nus_c_handles_assign(&m_ble_nus_c[p_gap_evt->conn_handle], p_gap_evt->conn_handle, NULL);
            err_code = ble_nus_c_handles_assign(&m_ble_nus_c[p_gap_evt->conn_handle], p_ble_evt->evt.gap_evt.conn_handle, NULL);
            
            NRF_LOG_INFO("m_ble_nus_c[0x%x]: conn_handle = 0x%x, rx = 0x%x, tx = 0x%x, cccd = 0x%x",
                p_gap_evt->conn_handle,
                m_ble_nus_c[p_gap_evt->conn_handle].conn_handle,
                m_ble_nus_c[p_gap_evt->conn_handle].handles.nus_rx_handle,
                m_ble_nus_c[p_gap_evt->conn_handle].handles.nus_tx_handle,
                m_ble_nus_c[p_gap_evt->conn_handle].handles.nus_tx_cccd_handle);
            
            
            APP_ERROR_CHECK(err_code);

            //err_code = ble_db_discovery_start(&m_db_disc, p_ble_evt->evt.gap_evt.conn_handle);

          //err_code = ble_db_discovery_start(&m_db_disc, p_gap_evt->conn_handle);
          err_code = ble_db_discovery_start(&m_db_disc, p_ble_evt->evt.gap_evt.conn_handle);

            if (err_code != NRF_ERROR_BUSY)
            {
                APP_ERROR_CHECK(err_code);
            }

            // Update LEDs status, and check if we should be looking for more
            // peripherals to connect to.
            bsp_board_led_on(CENTRAL_CONNECTED_LED);
            if (ble_conn_state_n_centrals() == NRF_SDH_BLE_CENTRAL_LINK_COUNT)
            {
                bsp_board_led_off(CENTRAL_SCANNING_LED);
            }
            else
            {
                // Resume scanning.
               bsp_board_led_on(CENTRAL_SCANNING_LED);
               scan_start();
            }
        } break; // BLE_GAP_EVT_CONNECTED

        // Upon disconnection, reset the connection handle of the peer which disconnected, update
        // the LEDs status and start scanning again.
        case BLE_GAP_EVT_DISCONNECTED:
        {
            NRF_LOG_INFO("Central link 0x%x disconnected (reason: 0x%x)",
                         p_gap_evt->conn_handle,
                         p_gap_evt->params.disconnected.reason);

            if (ble_conn_state_n_centrals() == 0)
            {
                //err_code = app_button_disable();
                //APP_ERROR_CHECK(err_code);

                // Turn off connection indication LED
                bsp_board_led_off(CENTRAL_CONNECTED_LED);
            }

            // Start scanning
            scan_start();

            // Turn on LED for indicating scanning
            bsp_board_led_on(CENTRAL_SCANNING_LED);

        } break;

        case BLE_GAP_EVT_ADV_REPORT:
            on_adv_report(p_ble_evt);
            break;

        case BLE_GAP_EVT_TIMEOUT:
        {
            // We have not specified a timeout for scanning, so only connection attemps can timeout.
            if (p_gap_evt->params.timeout.src == BLE_GAP_TIMEOUT_SRC_CONN)
            {
                NRF_LOG_DEBUG("Connection request timed out.");
            }
        } break;

        case BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST:
        {
            NRF_LOG_DEBUG("BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST.");
            // Accept parameters requested by peer.
            err_code = sd_ble_gap_conn_param_update(p_gap_evt->conn_handle,
                                        &p_gap_evt->params.conn_param_update_request.conn_params);
            APP_ERROR_CHECK(err_code);
        } break;

#ifndef S140
        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;
#endif

        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 interrupts.
 */
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 handling database discovery events.
 *
 * @details This function is callback function to handle events from the database discovery module.
 *          Depending on the UUIDs that are discovered, this function should forward the events
 *          to their respective services.
 *
 * @param[in] p_event  Pointer to the database discovery event.
 */
static void db_disc_handler(ble_db_discovery_evt_t * p_evt)
{
    NRF_LOG_DEBUG("call to ble_lbs_on_db_disc_evt for instance %d and link 0x%x!",
                  p_evt->conn_handle,
                  p_evt->conn_handle);

    ble_nus_c_on_db_disc_evt(&m_ble_nus_c[p_evt->conn_handle], p_evt);
}

/**@brief Function for handling characters received by the Nordic UART Service.
 *
 * @details This function takes a list of characters of length data_len and prints the characters out on UART.
 *          If @ref ECHOBACK_BLE_UART_DATA is set, the data is sent back to sender.
 */
static void ble_nus_chars_received_uart_print(uint8_t * p_data, uint16_t data_len)
{
    ret_code_t ret_val;

    NRF_LOG_DEBUG("Receiving data.");
    NRF_LOG_HEXDUMP_DEBUG(p_data, data_len);

    for (uint32_t i = 0; i < data_len; i++)
    {
        do
        {
            ret_val = app_uart_put(p_data[i]);
            if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
            {
                NRF_LOG_ERROR("app_uart_put failed for index 0x%04x.", i);
                APP_ERROR_CHECK(ret_val);
            }
        } while (ret_val == NRF_ERROR_BUSY);
    }
    if (p_data[data_len-1] == '\r')
    {
        while (app_uart_put('\n') == NRF_ERROR_BUSY);
    }
   /* if (ECHOBACK_BLE_UART_DATA)
    {
        // Send data back to peripheral.

        do
        {   
        for(uint32_t i = 0; i< NRF_SDH_BLE_CENTRAL_LINK_COUNT; i++)
        {
            ret_val = ble_nus_c_string_send(&m_ble_nus_c[i], p_data, data_len);
            if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
            {
                NRF_LOG_ERROR("Failed sending NUS message. Error 0x%x. ", ret_val);
                APP_ERROR_CHECK(ret_val);
            }
            }
        } while (ret_val == NRF_ERROR_BUSY);

    }
    */
}


/**@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.
 */
void uart_event_handle(app_uart_evt_t * p_event)
{
    uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
    uint16_t index = 0;
    uint32_t ret_val = NRF_ERROR_INVALID_STATE;

    switch (p_event->evt_type)
    {
        /**@snippet [Handling data from UART] */
        case APP_UART_DATA_READY:
            UNUSED_VARIABLE(app_uart_get(&data_array[index]));
            index++;

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

                for (uint32_t i = 0; i < NRF_SDH_BLE_CENTRAL_LINK_COUNT; i++) {
                  if (m_ble_nus_c[i].conn_handle != BLE_CONN_HANDLE_INVALID && 
                    0 != m_ble_nus_c[i].handles.nus_tx_handle && 
                    0 != m_ble_nus_c[i].handles.nus_rx_handle )
                  {
                    ret_val = ble_nus_c_string_send(&m_ble_nus_c[i], data_array, index);

                    if ((ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_BUSY)) {
                      NRF_LOG_ERROR("CON HND id is %d, UUID %d, Tx %d, Rx %d, RETVAL %d",
                          m_ble_nus_c[i].conn_handle,
                          m_ble_nus_c[i].uuid_type,
                          m_ble_nus_c[i].handles.nus_tx_handle,
                          m_ble_nus_c[i].handles.nus_rx_handle,
                          ret_val);
                      //APP_ERROR_CHECK(ret_val);
                    }
                  }
                }

                index = 0;
            }
            break;

        /**@snippet [Handling data from UART] */
        case APP_UART_COMMUNICATION_ERROR:
            NRF_LOG_ERROR("Communication error occurred while handling UART.");
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:
            NRF_LOG_ERROR("Error occurred in FIFO module used by UART.");
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}


/**@brief Callback handling NUS Client events.
 *
 * @details This function is called to notify the application of NUS client events.
 *
 * @param[in]   p_ble_nus_c   NUS Client Handle. This identifies the NUS client
 * @param[in]   p_ble_nus_evt Pointer to the NUS Client event.
 */

/**@snippet [Handling events from the ble_nus_c module] */
static void ble_nus_c_evt_handler(ble_nus_c_t * p_ble_nus_c, ble_nus_c_evt_t const * p_ble_nus_evt)
{
    ret_code_t err_code;

    switch (p_ble_nus_evt->evt_type)
    {
        case BLE_NUS_C_EVT_DISCOVERY_COMPLETE:
            NRF_LOG_INFO("Discovery on handle %d complete.", p_ble_nus_evt->conn_handle);

            //  Burasi GAP event, discovery event degil. Burayý deðiþtirmek lazým

            err_code = ble_nus_c_handles_assign(&p_ble_nus_c[p_ble_nus_evt->conn_handle], p_ble_nus_evt->conn_handle, &p_ble_nus_evt->handles);
            APP_ERROR_CHECK(err_code);

            NRF_LOG_INFO("m_ble_nus_c[0x%x]: conn_handle = 0x%x, rx = 0x%x, tx = 0x%x, cccd = 0x%x",
                                p_ble_nus_evt->conn_handle,
                                m_ble_nus_c[p_ble_nus_evt->conn_handle].conn_handle,
                                m_ble_nus_c[p_ble_nus_evt->conn_handle].handles.nus_rx_handle,
                                m_ble_nus_c[p_ble_nus_evt->conn_handle].handles.nus_tx_handle,
                                m_ble_nus_c[p_ble_nus_evt->conn_handle].handles.nus_tx_cccd_handle);
            

            err_code = ble_nus_c_tx_notif_enable(&p_ble_nus_c[p_ble_nus_evt->conn_handle]);
            
            //err_code = ble_nus_c_tx_notif_enable(p_ble_nus_c);
            if (err_code != NRF_ERROR_BUSY)
             {
                 APP_ERROR_CHECK(err_code);                                         
             }
            NRF_LOG_INFO("Connected to device with Nordic UART Service on handle %d.", p_ble_nus_evt->conn_handle);

            break;
        case BLE_NUS_C_EVT_NUS_TX_EVT:
            NRF_LOG_INFO("Uartttan data alindi.");
            ble_nus_chars_received_uart_print(p_ble_nus_evt->p_data, p_ble_nus_evt->data_len);
            break;

        case BLE_NUS_C_EVT_DISCONNECTED:
          NRF_LOG_INFO("Disconnected.");
          
          if( NULL == p_ble_nus_evt ) {
            NRF_LOG_INFO( "ple_ble_nus_evt is null" );
          }
          /*
          else if( BLE_CONN_HANDLE_INVALID != p_ble_nus_evt->conn_handle ) {
            NRF_LOG_INFO("m_ble_nus_c[0x%x]: DISCONNECTED = 0x%x, rx = 0x%x, tx = 0x%x, cccd = 0x%x",
                p_ble_nus_evt->conn_handle,
                m_ble_nus_c[p_ble_nus_evt->conn_handle].conn_handle,
                m_ble_nus_c[p_ble_nus_evt->conn_handle].handles.nus_rx_handle,
                m_ble_nus_c[p_ble_nus_evt->conn_handle].handles.nus_tx_handle,
                m_ble_nus_c[p_ble_nus_evt->conn_handle].handles.nus_tx_cccd_handle);
           }
           */
           else {
            NRF_LOG_INFO( "Event Handler connection pointer is null: conn_handle: %d", p_ble_nus_evt->conn_handle );
          }
          

          scan_start();
          break;
    }
}

/** @brief Database discovery initialization.
 */
static void db_discovery_init(void)
{
    ret_code_t err_code = ble_db_discovery_init(db_disc_handler);
    APP_ERROR_CHECK(err_code);
}


/** @brief Function to sleep until a BLE event is received by the application.
 */
static void power_manage(void)
{
    ret_code_t err_code = sd_app_evt_wait();
    APP_ERROR_CHECK(err_code);
}


/** @brief Function for initializing the 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 the timer.
 */
static void timer_init(void)
{
    ret_code_t err_code = app_timer_init();
    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);
        err_code = nrf_ble_gatt_att_mtu_central_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for initializing the UART. */
static void uart_init(void)
{
    ret_code_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,
        .baud_rate    = UART_BAUDRATE_BAUDRATE_Baud115200
    };

    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);
}

/**@brief Function for initializing the NUS Client. */
static void nus_c_init(void) 
{
  ret_code_t err_code;
  ble_nus_c_init_t init;
  init.evt_handler = ble_nus_c_evt_handler;
  for (uint32_t i = 0; i < NRF_SDH_BLE_CENTRAL_LINK_COUNT; i++) {
    err_code = ble_nus_c_init(&m_ble_nus_c[i], &init);
    APP_ERROR_CHECK(err_code);
  }

  /*
   ble_nus_c_init_t init[NRF_SDH_BLE_CENTRAL_LINK_COUNT];

  for(uint32_t i = 0; i< NRF_SDH_BLE_CENTRAL_LINK_COUNT; i++)
  {

    init[i].evt_handler = ble_nus_c_evt_handler;
    
    err_code = ble_nus_c_init(&m_ble_nus_c[i], &init[i]);
    APP_ERROR_CHECK(err_code);
    }
    */
}

int main(void)
{
    log_init();
    timer_init();
    leds_init();
    uart_init();
    ble_stack_init();
    gatt_init();
    db_discovery_init();
    //lbs_c_init();
    nus_c_init();
    ble_conn_state_init();
    NRF_LOG_INFO("Multilink example started.");

    // Start scanning for peripherals and initiate connection to devices which  advertise.
    scan_start();

    // Turn on the LED to signal scanning.
    bsp_board_led_on(CENTRAL_SCANNING_LED);

    for (;;)
    {
        if (!NRF_LOG_PROCESS())
        {
            power_manage();
        }
    }
}

 

I get no errors, but I should solve this "two times" problem. There should be a point that I failed to notice. Please help me on this. Thank you in advance.

By the way, same thing happens while sending data from central to peripherals. I mean, data is sent to handle 2, two times. :) but other handles receive the data as is is sent.

[Edvin]

Hello,

Do you get two events, or do you get twice the length on the data?

e.g.:

data = 1234512345 or data = 1122334455?

 

What does the log look like when you send one message from the device with conn handle 2?

Do you get the line: "Receiving data" two times? 

Can you also try to add, in your BLE_NUS_C_EVT_NUS_TX_EVT event:

NRF_LOG_INFO("Uartttan data alindi. conn_handle= %d", p_ble_nus_evt->conn_handle);

to see that you are not actually connected to the same device twice?

 

I assume that you have the same project/.hex-file on all the peripherals? Do you? do you have any #define ECHOBACK_BLE_UART_DATA in your peripheral project?

 

Best regards,

Edvin

 

[Seyma Tutuncu]

Hi,

I get the data as 1234512345 while I am sending 12345.

Only from one connection handle I get this.

For example:

From conn handle 0; I send 00 00 00 15 0A, then central gets  00 00 00 15 0A. I see "Uartttan data alindi" part one time. This is OK. 

From conn handle 2; I send  00 00 00 16 0A, then central gets 00 00 00 16 0A 00 00 00 16 0A. I see "Uartttan data alindi" part two times.

From conn handle 1; I send 00 00 00 17 0A, then central gets nothing. I don't see "Uartttan data alindi". After I reset conn handle 1, then it becomes conn handle 3, after that I send 00 00 00 17 0A then central get 00 00 00 17 0A. This time I see "Uartttan data alindi" part one time.

To conclude; handle 1 needs resetting to get data from central, and from conn handle 2, I get always 2 bytes consecutively.

I didn't use the ECHOBACK_BLE_UART_DATA, I removed it. Both central and peripherals.

I will consider what you say.

By the way, I have changed 

NRF_LOG_INFO("Uartttan data alindi.) part to

NRF_LOG_INFO("Uartttan data alindi. conn_handle= %d", p_ble_nus_evt->conn_handle); 

and I always see 

0> <info> app: Uartttan data alindi.conn_handle= 0
0> <info> app: Uartttan data alindi.conn_handle= 0

0> <info> app: Uartttan data alindi.conn_handle= 0

0> <info> app: Uartttan data alindi.conn_handle= 0

0> <info> app: Uartttan data alindi.conn_handle= 0

from every connection handle. I get two times for handle 2, and one time for handle 0. But for every handle it says conn handle 0. I didn't understand. Because at first central assigns handles correctly at the time of connection. 

[Edvin]

Hello,

 

Is it possible to send the central project? Do you use any special HW, such as sensors? Or can I replicate this on the regular DK?

 

Best regards,

Edvin

[Seyma Tutuncu]

Hi,

Link for the central  project file is here. Also I added the .rar file. I use only EYSHSNZWZ board, there isn't any other specific HW. I have only changed the pins for LEDs and there is not any other difference, I think you can use it.

Thank you.

0474.ble_app_multilink_central.rar

[Edvin]

Hello,

I am not able to compile your project. I get a lot of weird compiling errors, but I suspect that it is because you have modified the ble_nus_c.c and ble_nus_c.h files, which does not originally have BLE_NUS_C_ARRAY_DEF in SDK14.2.0.

 

Try to compile the project that you sent in a freshly unzipped SDK, and see what files that are missing. These are the files that I would need to compile.

 

Can you check one thing: Does the same behavior occur if you try to disable optimization? In SES you do this in project settings->code->code generation->optimization level.

 

It may be that the ble_nus_c.c does not pass the conn_handle correctly, since it is originally intended for only one connection (at least in SDK14.2.0).

 

Can you try to add the conn_handle in the on_hvx() function in ble_nus_c.c.

Change from:

static void on_hvx(ble_nus_c_t * p_ble_nus_c, ble_evt_t const * p_ble_evt)
{
    // HVX can only occur from client sending.
    if (   (p_ble_nus_c->handles.nus_tx_handle != BLE_GATT_HANDLE_INVALID)
        && (p_ble_evt->evt.gattc_evt.params.hvx.handle == p_ble_nus_c->handles.nus_tx_handle)
        && (p_ble_nus_c->evt_handler != NULL))
    {
        ble_nus_c_evt_t ble_nus_c_evt;

        ble_nus_c_evt.evt_type = BLE_NUS_C_EVT_NUS_TX_EVT;
        ble_nus_c_evt.p_data   = (uint8_t *)p_ble_evt->evt.gattc_evt.params.hvx.data;
        ble_nus_c_evt.data_len = p_ble_evt->evt.gattc_evt.params.hvx.len;

        p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);
        NRF_LOG_DEBUG("Client sending data.");
    }
}

to:

static void on_hvx(ble_nus_c_t * p_ble_nus_c, ble_evt_t const * p_ble_evt)
{
    // HVX can only occur from client sending.
    if (   (p_ble_nus_c->handles.nus_tx_handle != BLE_GATT_HANDLE_INVALID)
        && (p_ble_evt->evt.gattc_evt.params.hvx.handle == p_ble_nus_c->handles.nus_tx_handle)
        && (p_ble_nus_c->evt_handler != NULL))
    {
        ble_nus_c_evt_t ble_nus_c_evt;

        ble_nus_c_evt.conn_handle = p_ble_nus_c->conn_handle;
        ble_nus_c_evt.evt_type = BLE_NUS_C_EVT_NUS_TX_EVT;
        ble_nus_c_evt.p_data   = (uint8_t *)p_ble_evt->evt.gattc_evt.params.hvx.data;
        ble_nus_c_evt.data_len = p_ble_evt->evt.gattc_evt.params.hvx.len;

        p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);
        NRF_LOG_DEBUG("Client sending data.");
    }
}