RE: Uart BLE multilink

Bjørn Kvaale — Mon, 05 Nov 2018 14:53:26 GMT

Have you tried testing with the regular multilink central plus two peripheral uart examples before you merged the multilink central with uart central? I have just tested this now & that worked fine.

Is this all the logging you receive before you get the error?

The error 8 NRF_ERROR_INVALID_STATE only occurs under one of the following three conditions:

 * @retval ::NRF_ERROR_INVALID_STATE Invalid state to perform operation. Either:
 *                                   - Scanning is already ongoing and p_scan_params was not NULL
 *                                   - Scanning is not running and p_scan_params was NULL.
 *                                   - The scanner has timed out when this function is called to continue scanning.

From your last comment, it seems that m_scan in the call null, correct? That would make sense then that the sd_ble_gap_scan_start() inside nrf_ble_scan_start() in nrf_ble_scan.c returns error code 8. Also, from your logging, it seems you did not receive any logging info from:

NRF_LOG_ERROR("sd_ble_gap_scan_start returned 0x%x", err_code);

Is this a correct assumption? It seems like it has to be the second case in the comment above, as scanning is not already ongoing & the scanner did not timeout.

RE: Uart BLE multilink

l.r.97 — Tue, 30 Oct 2018 07:12:53 GMT

I changed the sdk version to 15.2 last week. Even the verse with the name change brought no success. The sd_ble_gap_scan_start () function returns the error_code 8, that is, the invalid_state. However, after the description of the status, this error_code can not be called because the scan is already running and I pass the parameter NULL, as described in the function.
Here is the current version of the code.

/**
 * Copyright (c) 2016 - 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 <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include "nordic_common.h"
#include "app_error.h"
#include "app_uart.h"
#include "ble_db_discovery.h"
#include "app_timer.h"
#include "app_util.h"
#include "bsp_btn_ble.h"
#include "ble.h"
#include "ble_gap.h"
#include "ble_hci.h"
#include "nrf_sdh.h"
#include "nrf_sdh_ble.h"
#include "nrf_sdh_soc.h"
#include "ble_advdata.h"
#include "ble_nus_c.h"
#include "nrf_ble_gatt.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_drv_uart.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrf_ble_scan.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 BLE_CONN_CFG_TAG_DEFAULT. */
#define APP_BLE_OBSERVER_PRIO   3                                       /**< Application's BLE observer priority. You shoulnd't need to modify this value. */

#define UART_TX_BUF_SIZE        1024                                     /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE        1024                                     /**< UART RX buffer size. */

#define NUS_SERVICE_UUID_TYPE   BLE_UUID_TYPE_VENDOR_BEGIN              /**< UUID type for the Nordic UART Service (vendor specific). */

#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_DURATION           0x0000                                  /**< Timout when scanning. 0x0000 disables timeout. */

#define MIN_CONNECTION_INTERVAL MSEC_TO_UNITS(20, UNIT_1_25_MS)         /**< Determines minimum connection interval in millisecond. */
#define MAX_CONNECTION_INTERVAL MSEC_TO_UNITS(75, UNIT_1_25_MS)         /**< Determines maximum connection interval in millisecond. */
#define SLAVE_LATENCY           0                                       /**< Determines slave latency in counts of connection events. */
#define SUPERVISION_TIMEOUT     MSEC_TO_UNITS(4000, UNIT_10_MS)         /**< Determines supervision time-out in units of 10 millisecond. */

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


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

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. */
static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
static uint8_t data_crc[BLE_NUS_MAX_DATA_LEN];
void uart_event_handle(app_uart_evt_t * p_event);
static char const m_target_periph_name[] = "Nordic_UART"; 

/**@brief Connection parameters requested for connection. */
static ble_gap_conn_params_t const m_connection_param =
{
    (uint16_t)MIN_CONNECTION_INTERVAL,  // Minimum connection
    (uint16_t)MAX_CONNECTION_INTERVAL,  // Maximum connection
    (uint16_t)SLAVE_LATENCY,            // Slave latency
    (uint16_t)SUPERVISION_TIMEOUT       // Supervision time-out
};

static uint8_t m_scan_buffer_data[BLE_GAP_SCAN_BUFFER_MIN]; /**< buffer where advertising reports will be stored by the SoftDevice. */

/**@brief Pointer to the buffer where advertising reports will be stored by the SoftDevice. */
static ble_data_t m_scan_buffer =
{
    m_scan_buffer_data,
    BLE_GAP_SCAN_BUFFER_MIN
};

/** @brief Parameters used when scanning. */
static ble_gap_scan_params_t const m_scan_params =
{
    .active   = 1,
    .interval = SCAN_INTERVAL,
    .window   = SCAN_WINDOW,
    .timeout          = SCAN_DURATION,
    .scan_phys        = BLE_GAP_PHY_1MBPS,
    .filter_policy    = BLE_GAP_SCAN_FP_ACCEPT_ALL,
};

/**@brief NUS uuid. */
static ble_uuid_t const m_nus_uuid =
{
    .uuid = BLE_UUID_NUS_SERVICE,
    .type = NUS_SERVICE_UUID_TYPE
};

static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
    ret_code_t err_code;

    switch(p_scan_evt->scan_evt_id)
    {
        case NRF_BLE_SCAN_EVT_CONNECTING_ERROR:
        {
            err_code = p_scan_evt->params.connecting_err.err_code;
            APP_ERROR_CHECK(err_code);
        } break;

        default:
            break;
    }
}

static void scan_init(void)
{
    ret_code_t          err_code;
    nrf_ble_scan_init_t init_scan;

    memset(&init_scan, 0, sizeof(init_scan));

    init_scan.connect_if_match = true;
    init_scan.conn_cfg_tag     = APP_BLE_CONN_CFG_TAG;

    err_code = nrf_ble_scan_init(&m_scan, &init_scan, scan_evt_handler);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_NAME_FILTER, m_target_periph_name);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_NAME_FILTER, false);
    APP_ERROR_CHECK(err_code);
}
/**@brief 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] 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 to start scanning. */
static void scan_start(void)
{
    ret_code_t ret;

    NRF_LOG_INFO("Start scanning for device name %s.", (uint32_t)m_target_periph_name);
    ret = nrf_ble_scan_start(&m_scan);
    APP_ERROR_CHECK(ret);
    // Turn on the LED to signal scanning.
    bsp_board_led_invert(BSP_BOARD_LED_3);
}


/**@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 uint32_t ble_nus_chars_received_uart_print(uint8_t * p_data, uint16_t data_len)
{
    ret_code_t ret_val;
    uint8_t byte[1024] = {0}; 
    uint32_t check = 0;

    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
        {
            ret_val = ble_nus_c_string_send(m_ble_nus_c, 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);
    }
    for (uint32_t i = 0; i < data_len; i++)
        {
          byte[i] = p_data[i];
        }
    bsp_board_led_invert(BSP_BOARD_LED_0);
    return nrf_drv_uart_tx(&app_uart_inst,byte,data_len); 

}


/**@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)
{
    
    static uint16_t index = 0;
    uint8_t rx_byte;
    uint32_t ret_val;
    uint32_t get_state;

    switch (p_event->evt_type)
    {
        /**@snippet [Handling data from UART] */
        case APP_UART_DATA_READY:
          
           do
          {
             get_state = app_uart_get(&rx_byte);
             if(get_state == NRF_SUCCESS)
             {
               data_array[index] = rx_byte;
               if( data_array[index] == 0x03  || index + 1 >= m_ble_nus_max_data_len )
               {

                   bsp_board_led_invert(BSP_BOARD_LED_0);
                    NRF_LOG_DEBUG("Ready to send data over BLE NUS");
                    NRF_LOG_HEXDUMP_DEBUG(data_array, index);

                    if(m_ble_nus_c->conn_handle != BLE_CONN_HANDLE_INVALID)
                    {

                      do
                      {
                          ret_val = ble_nus_c_string_send(m_ble_nus_c, data_array, index);
                          if(0)
                          {
                              APP_ERROR_CHECK(ret_val);
               
                          }
                      } while (ret_val == NRF_ERROR_BUSY);            
                    }
                    index = 0;                    
               }
                else
                {              
                  index++;
                  if(index > sizeof(data_array))
                  {
                    index = 0;
                  } 
                }
              }
          }
          while(get_state == NRF_SUCCESS);
          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 complete.");
            err_code = ble_nus_c_handles_assign(p_ble_nus_c, p_ble_nus_evt->conn_handle, &p_ble_nus_evt->handles);
            APP_ERROR_CHECK(err_code);

            err_code = ble_nus_c_tx_notif_enable(p_ble_nus_c);
            APP_ERROR_CHECK(err_code);
            NRF_LOG_INFO("Connected to device with Nordic UART Service.");
            break;

        case BLE_NUS_C_EVT_NUS_TX_EVT:
            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.");
            scan_start();
            break;
    }
}
/**@snippet [Handling events from the ble_nus_c module] */


/**
 * @brief Function for shutdown events.
 *
 * @param[in]   event       Shutdown type.
 */
static bool shutdown_handler(nrf_pwr_mgmt_evt_t event)
{
    ret_code_t err_code;

    err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    switch (event)
    {
        case NRF_PWR_MGMT_EVT_PREPARE_WAKEUP:
            // Prepare wakeup buttons.
            err_code = bsp_btn_ble_sleep_mode_prepare();
            APP_ERROR_CHECK(err_code);
            break;

        default:
            break;
    }

    return true;
}

NRF_PWR_MGMT_HANDLER_REGISTER(shutdown_handler, APP_SHUTDOWN_HANDLER_PRIORITY);


/**@brief Function for handling the advertising report BLE event.
 *
 * @param[in] p_adv_report  Advertising report from the SoftDevice.
 */
static void on_adv_report(ble_gap_evt_adv_report_t const * p_adv_report)
{
    ret_code_t err_code;
      
    NRF_LOG_INFO("Packet received");
      

    if (ble_advdata_name_find(p_adv_report->data.p_data,
                              p_adv_report->data.len,
                              m_target_periph_name))
    {
        NRF_LOG_INFO("Device name found");
        err_code = sd_ble_gap_scan_start(NULL, &m_scan_buffer);
        APP_ERROR_CHECK(err_code);
    }
    else
    {
        err_code = sd_ble_gap_scan_start(NULL, &m_scan_buffer);
        APP_ERROR_CHECK(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;
    ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_ADV_REPORT:
            on_adv_report(&p_gap_evt->params.adv_report);
            break; // BLE_GAP_EVT_ADV_REPORT

        case BLE_GAP_EVT_CONNECTED:
            NRF_LOG_INFO("Connection 0x%x established, starting DB discovery.",
                         p_gap_evt->conn_handle);
            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);
            APP_ERROR_CHECK(err_code);

            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            err_code = ble_db_discovery_start(&m_db_disc[p_gap_evt->conn_handle],
                                              p_gap_evt->conn_handle);
            // start discovery of services. The NUS Client waits for a discovery result
            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);
            }
            break;

        case BLE_GAP_EVT_TIMEOUT:
            if (p_gap_evt->params.timeout.src == BLE_GAP_TIMEOUT_SRC_SCAN)
            {
                NRF_LOG_INFO("Scan timed out.");
                scan_start();
            }
            else if (p_gap_evt->params.timeout.src == BLE_GAP_TIMEOUT_SRC_CONN)
            {
                NRF_LOG_INFO("Connection Request timed out.");
                
            }
            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_CONN_PARAM_UPDATE_REQUEST:
            // Accepting 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;

        case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
        {
            NRF_LOG_DEBUG("PHY update request.");
            ble_gap_phys_t const phys =
            {
                .rx_phys = BLE_GAP_PHY_AUTO,
                .tx_phys = BLE_GAP_PHY_AUTO,
            };
            err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
            APP_ERROR_CHECK(err_code);
        } break;

        case BLE_GATTC_EVT_TIMEOUT:
            // Disconnect on GATT Client timeout event.
            NRF_LOG_DEBUG("GATT Client Timeout.");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            NRF_LOG_DEBUG("GATT Server Timeout.");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

        default:
            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 handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED)
    {
        NRF_LOG_INFO("ATT MTU exchange completed.");

        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Ble NUS max data length set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
}


/**@brief Function for initializing the GATT library. */
void gatt_init(void)
{
    ret_code_t err_code;

    err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
    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 handling events from the BSP module.
 *
 * @param[in] event  Event generated by button press.
 */
void bsp_event_handler(bsp_event_t event)
{
    ret_code_t err_code;

    switch (event)
    {
        case BSP_EVENT_SLEEP:
            nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);
            break;

        case BSP_EVENT_DISCONNECT:
            err_code = sd_ble_gap_disconnect(m_ble_nus_c->conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break;

        default:
            break;
    }
}

/**@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;

    err_code = ble_nus_c_init(m_ble_nus_c, &init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for initializing buttons and leds. */
static void buttons_leds_init(void)
{
    ret_code_t err_code;
    bsp_event_t startup_event;

    err_code = bsp_init(BSP_INIT_LEDS, bsp_event_handler);
    err_code = bsp_init(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);
}


/**@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 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 initializing the Database Discovery Module. */
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 for handling the idle state (main loop).
 *
 * @details Handle any pending log operation(s), then sleep until the next event occurs.
 */
static void idle_state_handle(void)
{
    if (NRF_LOG_PROCESS() == false)
    {
        nrf_pwr_mgmt_run();
    }
}


int main(void)
{
    // Initialize.
    
    log_init();
    timer_init();
    uart_init();
    buttons_leds_init();
    db_discovery_init();
    power_management_init();
    ble_stack_init();
    gatt_init();
    nus_c_init();
    scan_init();

    // Start execution.
    printf("BLE UART central example started.\r\n");
    NRF_LOG_INFO("BLE UART central example started.");
    scan_start();

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

RE: Uart BLE multilink

Bjørn Kvaale — Mon, 29 Oct 2018 13:22:59 GMT

Did you have to set the DEBUG flag to get it working. SDK v15.1.0 has had a few issues summarized in the release_notes.txt of sdk v15.2.0. The main highlights are summarized below:

"-Removed the workaround in nrf_sdh.c overriding the default priority level on SWI interrupt SD_EVT_IRQn and RADIO_NOTIFICATION_IRQn used by the SoftDevice.
- Changed the default interrupt priority level for the peripherals from 7 to 6. This is done to be aligned with the priority of the SWI coming from the SoftDevice.
- Fixed an interoperability issue with some Windows 10 versions when bonded and using directed advertising."

If you take a look at the multilink documentation, you notice that the board will automatically connect to any devices that have the device name "Nordic_Blinky". The multilink example works out of the box with the ble blinky application, not the uart application.

Have you tried changing the device names of the peripheral devices to Nordic_Blinky? Does that fix the issue?

If you are still noticing issues, I would suggest trying with the latest nRF5 SDK.

RE: Uart BLE multilink

l.r.97 — Tue, 23 Oct 2018 13:13:53 GMT

No, I use the 15.1.0 one. The problem I have already solved. The board is now starting to scan. However, no connection to the peripheral can be established. See the following pictures. Why can not I connect? The optimizations are deactivated. The RAM size has been adjusted according to the following picture and activated in NRF_BLE_SCAN_NAME_CNT instead of NRF_BLE_SCAN_UUID_CNT. In addition, I call now the initialization function of the scan in the main. I forgot that in the previous code.

RE: Uart BLE multilink

Bjørn Kvaale — Tue, 23 Oct 2018 12:56:47 GMT

Are you using nRF5 sdk 15.2.0?