BLE UART on SDK15.3. Long Range connection problem

[tparkkila]

Hi,

I have the following setup:

- IDE: SES

- SDK: nRF5_SDK_15.3.0_59ac345

- SD: s140_nrf52_6.1.1_softdevice.hex

Issue description:

I have modified "ble_app_uart_c" and "ble_app_uart" examples to support CODED_PHY (i.e. long range) communication coding, but with mixed results.

1. Testing with two PCA10056 (v0.9.2) development kits, central doesn't receive advertisement packets even,

2. Testing peripheral code (based on "ble_app_uart" example) with our custom board, central finds advertisement packets and tries to connect to peripheral, but connection is dropped with code 62.

Couple options for support requests:

1. Please point me to right directions to find an example for modified "ble_app_uart" with long range coding, or 

2. Check the attached projects and src to give me hints and guidance what I am missing in the code? (Pls. see the attachments at the end of the message)

Any help would be highly appreciated!

Regards,

-Tommi Parkkila

Attachements:

1. SRC: ble_uart_peripheral_main.c

Fullscreen ble_uart_peripheral_main.c Download

/**
 * Copyright (c) 2014 - 2019, 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.
 *
 */
/** @file
 *
 * @defgroup ble_sdk_uart_over_ble_main main.c
 * @{
 * @ingroup  ble_sdk_app_nus_eval
 * @brief    UART over BLE application main file.
 *
 * This file contains the source code for a sample application that uses the Nordic UART service.
 * This application uses the @ref srvlib_conn_params module.
 */


#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_qwr.h"
#include "app_timer.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"
#include "bsp_btn_ble.h"
#include "nrf_pwr_mgmt.h"

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

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

#define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */

#define DEVICE_NAME                     "BLE5_UART"                               /**< Name of device. Will be included in the advertising data. */
#define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN                  /**< UUID type for the Nordic UART Service (vendor specific). */

#define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */

#define APP_ADV_INTERVAL                64                                          /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */

#define APP_ADV_DURATION                18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(7.5, UNIT_1_25_MS)             /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(500, UNIT_1_25_MS)             /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
#define SLAVE_LATENCY                   0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define 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. */

//#define BLE_LONG_RANGE_ENABLE
// LED pins
#define PIN_GREEN_LED         (NRF_GPIO_PIN_MAP(1,13))
#define PIN_RED_LED           (NRF_GPIO_PIN_MAP(1,15))
#define PIN_BLUE_LED          (NRF_GPIO_PIN_MAP(1,10))

BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */
NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */

static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
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. */
static ble_uuid_t m_adv_uuids[]          =                                          /**< Universally unique service identifier. */
{
    {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
};

// UART pins
#define UART_RX_PIN_NUMBER    8 //20 // 8
#define UART_TX_PIN_NUMBER    6// 17 // 6
#define UART_CTS_PIN_NUMBER   (0xFFFFFFFFUL)
#define UART_RTS_PIN_NUMBER   (0xFFFFFFFFUL)

static void led_on(uint32_t lednumber){
  nrf_gpio_cfg_output(lednumber);
  nrf_gpio_pin_clear(lednumber);
}

static void led_toggle(uint32_t lednumber){
  nrf_gpio_cfg_output(lednumber);
  nrf_gpio_pin_toggle(lednumber);
}

static void led_off(uint32_t lednumber){
  nrf_gpio_cfg_output(lednumber);
  nrf_gpio_pin_set(lednumber);
}
static void led_off_all(void){
    nrf_gpio_cfg_output(PIN_RED_LED);
    nrf_gpio_pin_set(PIN_RED_LED);

    nrf_gpio_cfg_output(PIN_GREEN_LED);
    nrf_gpio_pin_set(PIN_GREEN_LED);

    nrf_gpio_cfg_output(PIN_BLUE_LED);
    nrf_gpio_pin_set(PIN_BLUE_LED);
}

/**@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 analyse
 *          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);
}

/**@brief Function for initializing the timer module.
 */
static void timers_init(void)
{
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for the GAP initialization.
 *
 * @details This function will set up all the necessary GAP (Generic Access Profile) parameters of
 *          the device. It also sets the permissions and appearance.
 */
static void gap_params_init(void)
{
    uint32_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 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 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]);
                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 services that will be used by the application.
 */
static void services_init(void)
{
    uint32_t           err_code;
    ble_nus_init_t     nus_init;
    nrf_ble_qwr_init_t qwr_init = {0};

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

    err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
    APP_ERROR_CHECK(err_code);

    // 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);
}


/**@brief Function for handling an event from the Connection Parameters Module.
 *
 * @details This function will be called for all events in the Connection Parameters Module
 *          which are passed to the application.
 *
 * @note All this function does is to disconnect. This could have been done by simply setting
 *       the disconnect_on_fail config parameter, but instead we use the event handler
 *       mechanism to demonstrate its use.
 *
 * @param[in] p_evt  Event received from the Connection Parameters Module.
 */
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
{
    uint32_t err_code;

    if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
    {
        err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
        APP_ERROR_CHECK(err_code);
    }
}


/**@brief Function for handling errors from the Connection Parameters module.
 *
 * @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)
{
    uint32_t               err_code;
    ble_conn_params_init_t cp_init;

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

    cp_init.p_conn_params                  = NULL;
    cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
    cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
    cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
    cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
    cp_init.disconnect_on_fail             = false;
    cp_init.evt_handler                    = on_conn_params_evt;
    cp_init.error_handler                  = conn_params_error_handler;

    err_code = ble_conn_params_init(&cp_init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for putting the chip into sleep mode.
 *
 * @note This function will not return.
 */
static void sleep_mode_enter(void)
{
    uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    // Prepare wakeup buttons.
    err_code = bsp_btn_ble_sleep_mode_prepare();
    APP_ERROR_CHECK(err_code);

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling advertising events.
 *
 * @details This function will be called for advertising events which are passed to the application.
 *
 * @param[in] ble_adv_evt  Advertising event.
 */
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
    uint32_t err_code;

    switch (ble_adv_evt)
    {
        case BLE_ADV_EVT_FAST:
            err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
            APP_ERROR_CHECK(err_code);
            break;
        case BLE_ADV_EVT_IDLE:
            sleep_mode_enter();
            break;
        default:
            break;
    }
}


/**@brief Function for handling BLE events.
 *
 * @param[in]   p_ble_evt   Bluetooth stack event.
 * @param[in]   p_context   Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    uint32_t err_code;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            NRF_LOG_INFO("Connected");
            led_on(PIN_BLUE_LED);
            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:
            
            NRF_LOG_INFO("Disconnected %d", p_ble_evt->evt.gap_evt.params.disconnected.reason);
            led_off_all();
            // LED indication will be changed when advertising starts.
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            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_GAP_EVT_SEC_PARAMS_REQUEST:
            // Pairing not supported
            err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
            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(m_conn_handle, NULL, 0, 0);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTC_EVT_TIMEOUT:
            // Disconnect on GATT Client timeout event.
            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.
            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 the SoftDevice initialization.
 *
 * @details This function 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 ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
    {
        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
    NRF_LOG_DEBUG("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
                  p_gatt->att_mtu_desired_central,
                  p_gatt->att_mtu_desired_periph);
}


/**@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_periph_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)
{
    uint32_t err_code;
    switch (event)
    {
        case BSP_EVENT_SLEEP:
            sleep_mode_enter();
            break;

        case BSP_EVENT_DISCONNECT:
            err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break;

        case BSP_EVENT_WHITELIST_OFF:
            if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
            {
                err_code = ble_advertising_restart_without_whitelist(&m_advertising);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
            }
            break;

        default:
            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 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    = UART_RX_PIN_NUMBER,
        .tx_pin_no    = UART_TX_PIN_NUMBER,
        .rts_pin_no   = UART_RTS_PIN_NUMBER,
        .cts_pin_no   = UART_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 Advertising functionality.
 */
static void advertising_init(void)
{
    //TRY2
    uint32_t               err_code;
    ble_advertising_init_t init;

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

    init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance = false;
    init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;

#define BLE_LONG_RANGE
#ifdef BLE_LONG_RANGE
    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled     = true;
    init.config.ble_adv_fast_interval    = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout     = APP_ADV_DURATION;
    init.config.ble_adv_primary_phy      = BLE_GAP_PHY_CODED;
    init.config.ble_adv_secondary_phy    = BLE_GAP_PHY_CODED;
    init.config.ble_adv_extended_enabled = true;
#else
    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled     = true;
    init.config.ble_adv_fast_interval    = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout     = APP_ADV_DURATION;
    init.config.ble_adv_primary_phy      = BLE_GAP_PHY_1MBPS;
    init.config.ble_adv_secondary_phy    = BLE_GAP_PHY_1MBPS;
    init.config.ble_adv_extended_enabled = false;
#endif //BLE_LONG_RANGE

    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}


/**@brief Function for initializing buttons and leds.
 *
 * @param[out] p_erase_bonds  Will be true if the clear bonding button was pressed to wake the application up.
 */
static void buttons_leds_init(bool * p_erase_bonds)
{
    bsp_event_t startup_event;

    uint32_t err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, bsp_event_handler);
    APP_ERROR_CHECK(err_code);

    err_code = bsp_btn_ble_init(NULL, &startup_event);
    APP_ERROR_CHECK(err_code);

    *p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
}


/**@brief Function for initializing the nrf log module.
 */
static void log_init(void)
{
    ret_code_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();
}


/**@brief Function for initializing power management.
 */
static void power_management_init(void)
{
    ret_code_t err_code;
    err_code = nrf_pwr_mgmt_init();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling the idle state (main loop).
 *
 * @details If there is no pending log operation, then sleep until next the next event occurs.
 */
static void idle_state_handle(void)
{
    if (NRF_LOG_PROCESS() == false)
    {
        nrf_pwr_mgmt_run();
    }
}


/**@brief Function for starting advertising.
 */
static void advertising_start(void)
{
    uint32_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);
}


/**@brief Application main function.
 */
int main(void)
{
    bool erase_bonds;
    ret_code_t err_code; 

    // Initialize.
    uart_init();
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();

    // Start execution.
    printf("\r\n~~~UART started.~~~~\r\n");
    NRF_LOG_INFO("Debug logging for UART over RTT started.");
    advertising_start();
    err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV,  0, 8);
    APP_ERROR_CHECK(err_code);

    led_off(PIN_BLUE_LED);
    led_on(PIN_GREEN_LED);

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


/**
 * @}
 */

2. SRC: ble_uart_central_main.c:

Fullscreen ble_uart_central_main.c Download

/**
 * 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_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 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        256                                     /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE        256                                     /**< 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(7.5, UNIT_1_25_MS)         /**< Determines minimum connection interval in millisecond. */
#define MAX_CONNECTION_INTERVAL MSEC_TO_UNITS(500, 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_DEF(m_ble_nus_c);                                             /**< BLE NUS service client instance. */
NRF_BLE_GATT_DEF(m_gatt);                                               /**< GATT module instance. */
BLE_DB_DISCOVERY_DEF(m_db_disc);                                        /**< DB discovery module instance. */

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 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
};

#define BLE_LONG_RANGE
#ifdef BLE_LONG_RANGE
static uint8_t m_scan_buffer_data[BLE_GAP_SCAN_BUFFER_EXTENDED_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_EXTENDED_MIN
};

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

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


/**@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;

    ret = sd_ble_gap_scan_start(&m_scan_params, &m_scan_buffer);
    APP_ERROR_CHECK(ret);

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


/**@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)
{
    ble_nus_c_on_db_disc_evt(&m_ble_nus_c, 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_INFO("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);
    }
}


/**@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 uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
    static uint16_t index = 0;
    uint32_t ret_val;

    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_HEXDUMP_DEBUG(data_array, index);

                do
                {
                    ret_val = ble_nus_c_string_send(&m_ble_nus_c, data_array, index);
                    if ( (ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_BUSY) )
                    {
                        APP_ERROR_CHECK(ret_val);
                    }
                } while (ret_val == NRF_ERROR_BUSY);

                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 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("ADV. report");

    if (ble_advdata_uuid_find(p_adv_report->data.p_data, p_adv_report->data.len, &m_nus_uuid))
    {
        err_code = sd_ble_gap_connect(&p_adv_report->peer_addr,
                                      &m_scan_params,
                                      &m_connection_param,
                                      APP_BLE_CONN_CFG_TAG);

        if (err_code == NRF_SUCCESS)
        {
            // scan is automatically stopped by the connect
            err_code = bsp_indication_set(BSP_INDICATE_IDLE);
            APP_ERROR_CHECK(err_code);
            NRF_LOG_INFO("Connecting to target %02x%02x%02x%02x%02x%02x",
                     p_adv_report->peer_addr.addr[0],
                     p_adv_report->peer_addr.addr[1],
                     p_adv_report->peer_addr.addr[2],
                     p_adv_report->peer_addr.addr[3],
                     p_adv_report->peer_addr.addr[4],
                     p_adv_report->peer_addr.addr[5]
                     );
        }
    }
    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("Connected to target");
            err_code = ble_nus_c_handles_assign(&m_ble_nus_c, p_ble_evt->evt.gap_evt.conn_handle, NULL);
            APP_ERROR_CHECK(err_code);
            
            err_code = sd_ble_gap_rssi_start(p_ble_evt->evt.gap_evt.conn_handle, 10, 0);
            APP_ERROR_CHECK(err_code);

            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            

            // 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);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GAP_EVT_RSSI_CHANGED:
            NRF_LOG_INFO("RSSI : %d dBm", p_gap_evt->params.rssi_changed.rssi);
            break;

        case BLE_GAP_EVT_TIMEOUT:
            NRF_LOG_DEBUG("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:
            NRF_LOG_DEBUG("PAIRING update 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:
        
            NRF_LOG_DEBUG("CONN 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);
    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();

    // 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();
    }
}

[tparkkila]

One more thing:

Forgot to mention, that if I undefine BLE_LONG_RANGE(line 658 on ble_uart_peripheral_main.c, and line 101 on ble_uart_central_main.c) - pre-compilation flags everything works normally, advertisements are seen and connections are established normally. 

Thanks

[AndreasF]

Hi Tommi.

Have you had a look at this example on GitHub?

Best regards,

Andreas

[tparkkila]

Hi Andreas, no I haven't try this one. Even though it says its using SDK 15.3, I see the example is not using the same software architecture as SDK 15.3 uart examples. As for example on peripheral code in advertising_start function the SDK example uses function call:

- uint32_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST), whereas

- err_code = sd_ble_gap_adv_start(m_adv_handle, APP_BLE_CONN_CFG_TAG) function call is used by the github example you referred.

I know by looking at the source code of the stack that ble_advertising_start() function in ble_advertising.c file calls sd_ble_gap_adv_start() function eventually. Is there a way to configure settings in a such a way that the new SDK architecture can be utilized as it for Long Range comms?

I will try this project later today.

Thanks!

[tparkkila]

Hi Andreas - I tested the project you gave and get the similar results. Client is seen and connected but then immediately disconnected. See the debug logs below from peripheral project:

 app: Debug logging for UART over RTT started.

 nrf_ble_gatt: Requesting to update ATT MTU to 247 bytes on connection 0x0.

 app: Connected

 app: Disconnected

[AndreasF]

Hi.

What versions are your DK's?

There is an errata for Engineering B which causes poor communication link, ref.

Best regards,

Andreas

[tparkkila]

Not sure where to find the matching version number referred on the page you linked. I can find the following labels/numbers on devkits:

- on Atmel cpu: PCA10056, V0.9.2, 2017.33, 683964418

- on nRF52840 chip: N52840 QIAAAA 1716AK

[tparkkila]

Andreas - I got the example to work on our custom boards, which both have nRF52840 chip version: QIAAC0-1815AM.

Next, I will test the uart example code, which I modified and posted here originally.

[tparkkila]

Andreas - The modified ble_uart applications (as posted above) works with our custom boards as well. Therefore, the issue was with the dev kits hardware.

Thank you for your help!

[AndreasF]

Hi.

Great to hear :-)

Best regards,

Andreas