dynamic_electrocardiograph_ble_server/main.c

/**
 * Copyright (c) 2016 - 2021, 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 <stdbool.h>
#include <stdint.h>
#include <stdio.h>

#include "app_error.h"
#include "app_timer.h"
#include "app_uart.h"
#include "app_util.h"
#include "ble.h"
#include "ble_db_discovery.h"
#include "ble_gap.h"
#include "ble_hci.h"
#include "bsp_btn_ble.h"
#include "nordic_common.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_scan.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_sdh.h"
#include "nrf_sdh_ble.h"
#include "nrf_sdh_soc.h"
#include "zble_nus_c.h"

#define APP_BLE_CONN_CFG_TAG  1 /**< Tag that refers to the BLE stack configuration set with @ref sd_ble_cfg_set. The default tag is @ref BLE_CONN_CFG_TAG_DEFAULT. */
#define APP_BLE_OBSERVER_PRIO 3 /**< BLE observer priority of the application. There is no 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 ECHOBACK_BLE_UART_DATA 0 /**< Echo the UART data that is received over the Nordic UART Service (NUS) back to the sender. */

BLE_NUS_C_DEF(m_ble_nus_c);      /**< BLE Nordic UART Service (NUS) client instance. */
NRF_BLE_GATT_DEF(m_gatt);        /**< GATT module instance. */
BLE_DB_DISCOVERY_DEF(m_db_disc); /**< Database discovery module instance. */
NRF_BLE_SCAN_DEF(m_scan);        /**< Scanning Module instance. */
NRF_BLE_GQ_DEF(m_ble_gatt_queue, /**< BLE GATT Queue instance. */
               NRF_SDH_BLE_CENTRAL_LINK_COUNT, NRF_BLE_GQ_QUEUE_SIZE);

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

/**@brief Function for handling asserts in the SoftDevice.
 *
 * @details This function is called in case of an assert in the SoftDevice.
 *
 * @warning This handler is only an example and is not meant for the 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 handling the Nordic UART Service Client errors.
 *
 * @param[in]   nrf_error   Error code containing information about what went wrong.
 */
static void nus_error_handler(uint32_t nrf_error) { APP_ERROR_HANDLER(nrf_error); }

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

  ret = nrf_ble_scan_start(&m_scan);
  APP_ERROR_CHECK(ret);

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

/**@brief Function for handling Scanning Module events.
 */
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;

    case NRF_BLE_SCAN_EVT_CONNECTED: {
      ble_gap_evt_connected_t const* p_connected = p_scan_evt->params.connected.p_connected;
      // Scan is automatically stopped by the connection.
      NRF_LOG_INFO("Connecting to target %02x%02x%02x%02x%02x%02x", p_connected->peer_addr.addr[0], p_connected->peer_addr.addr[1], p_connected->peer_addr.addr[2], p_connected->peer_addr.addr[3], p_connected->peer_addr.addr[4], p_connected->peer_addr.addr[5]);
    } break;

    case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT: {
      NRF_LOG_INFO("Scan timed out.");
      scan_start();
    } break;

    default:
      break;
  }
}

/**@brief Function for initializing the scanning and setting the filters.
 */
static char m_target_periph_name0[20] = "M1002";   /**< Name of the device we try to connect to. This name is searched in the scan report data*/
static char m_target_periph_name1[20] = "M1001";   /**< Name of the device we try to connect to. This name is searched in the scan report data*/
static char m_target_periph_name2[20] = "iflytop"; /**< Name of the device we try to connect to. This name is searched in the scan report data*/
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_UUID_FILTER, &m_nus_uuid);
  // APP_ERROR_CHECK(err_code);

  APP_ERROR_CHECK(nrf_ble_scan_filter_set(&m_scan, SCAN_NAME_FILTER, m_target_periph_name0));
  APP_ERROR_CHECK(nrf_ble_scan_filter_set(&m_scan, SCAN_NAME_FILTER, m_target_periph_name1));
  APP_ERROR_CHECK(nrf_ble_scan_filter_set(&m_scan, SCAN_NAME_FILTER, m_target_periph_name2));

  // err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_NAME_FILTER, false);
  // 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 handling database discovery events.
 *
 * @details This function is a callback function to handle events from the database discovery module.
 *          Depending on the UUIDs that are discovered, this function forwards 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 (NUS).
 *
 * @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 app_uart_force_put(uint8_t data) {
  ret_code_t ret_val;
  do {
    ret_val = app_uart_put(data);
    if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY)) {
      NRF_LOG_ERROR("app_uart_put failed for index 0x%04x.", 0);
      APP_ERROR_CHECK(ret_val);
    }
  } while (ret_val == NRF_ERROR_BUSY);
}

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);
  app_uart_force_put(0x5A);
  app_uart_force_put(0xA5);
  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);
  }
  app_uart_force_put(0x5B);
  app_uart_force_put(0xB5);
}

static void ble_nus_chars_received_uart_print_ch4(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);
  app_uart_force_put(0x4A);
  app_uart_force_put(0xA4);
  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);
  }
  app_uart_force_put(0x4B);
  app_uart_force_put(0xB4);
}

/**@brief   Function for handling app_uart events.
 *
 * @details This function receives a single character from the app_uart module and appends it to
 *          a string. The string is sent over BLE when the last character received is a
 *          'new line' '\n' (hex 0x0A) or if the string reaches the maximum data length.
 */
static uint8_t  data_array[BLE_NUS_MAX_DATA_LEN];
static uint16_t data_array_index = 0;
// static uint32_t
void uart_event_handle(app_uart_evt_t* p_event) {
  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[data_array_index]));
      data_array_index++;

      if (data_array_index >= (m_ble_nus_max_data_len)) {
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        NRF_LOG_HEXDUMP_DEBUG(data_array, data_array_index);

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

        data_array_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 Nordic UART Service (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] */
typedef struct {
  uint32_t rxcnt;
  uint32_t m_rx_sum_cnt;
} block_data_rx_state_t;
block_data_rx_state_t block_data_rx_state;

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_NUS_TX_EVT_2:
#if 0
      block_data_rx_state.rxcnt += p_ble_nus_evt->data_len;
      for (size_t i = 0; i < p_ble_nus_evt->data_len; i++) {
        block_data_rx_state.m_rx_sum_cnt += p_ble_nus_evt->p_data[i];
      }
      ble_nus_chars_received_uart_print_ch4((uint8_t*)&block_data_rx_state, sizeof(block_data_rx_state));
#else
      ble_nus_chars_received_uart_print_ch4((uint8_t*)p_ble_nus_evt->p_data, p_ble_nus_evt->data_len);
#endif
      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 handling 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 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_CONNECTED:
      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 = 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_DISCONNECTED:

      NRF_LOG_INFO("Disconnected. conn_handle: 0x%x, reason: 0x%x", p_gap_evt->conn_handle, p_gap_evt->params.disconnected.reason);
      break;

    case BLE_GAP_EVT_TIMEOUT:
      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_Baud460800};

  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 Nordic UART Service (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;
  init.error_handler = nus_error_handler;
  init.p_gatt_queue  = &m_ble_gatt_queue;

  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) {
  ble_db_discovery_init_t db_init;

  memset(&db_init, 0, sizeof(ble_db_discovery_init_t));

  db_init.evt_handler  = db_disc_handler;
  db_init.p_gatt_queue = &m_ble_gatt_queue;

  ret_code_t err_code = ble_db_discovery_init(&db_init);
  APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling the idle state (main loop).
 *
 * @details Handles any pending log operations, then sleeps until the next event occurs.
 */
static void idle_state_handle(void) {
  if (NRF_LOG_PROCESS() == false) {
    nrf_pwr_mgmt_run();
  }
}
APP_TIMER_DEF(m_uart_send_tmr);  // ״̬��������ʱ��

static void uart_send_tmr_cb(void* p_context) {  //
  static uint32_t last_data_array_index;
  ret_code_t      ret_val;
  if (data_array_index != 0 && data_array_index == last_data_array_index) {
    do {
      ret_val = ble_nus_c_string_send(&m_ble_nus_c, data_array, data_array_index);
      if ((ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_RESOURCES)) {
        APP_ERROR_CHECK(ret_val);
      }
    } while (ret_val == NRF_ERROR_RESOURCES);
    data_array_index      = 0;
    last_data_array_index = 0;
  }
  last_data_array_index = data_array_index;
}
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();

  app_timer_create(&m_uart_send_tmr, APP_TIMER_MODE_REPEATED, uart_send_tmr_cb);
  app_timer_start(m_uart_send_tmr, APP_TIMER_TICKS(2), NULL);

  // 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();
  }
}