Nordic nRF5 SDK 学习笔记之三, 蓝牙 5 从机定时广播，待联结建立交换数据后，主动断开与主机的联结

硬件:  Central: nRF52840, Peripheral: nRF52832

SDK: Ver 15.0.0

目标: Peripheral 从机定时启动蓝牙广播，以及与主机联结，待交换完数据后，主动断开与主机的联结

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主要步骤:

1. 定义两个定时器 TIMER1, TIMER2; 

    TIMER1 用于从机蓝牙初始化及广播定时器; TIMER2 作为从机与主机断开的定时器；

APP_TIMER_DEF( bt_start_period_timer_id );
APP_TIMER_DEF( bt_cancel_period_timer_id );

#define BT_START_PERIOD_TIMER_INTERVAL    APP_TIMER_TICKS( 10000 )  // 10  秒
#define BT_CANCEL_PERIOD_TIMER_INTERVAL   APP_TIMER_TICKS( 100 )    // 100 毫秒

并于 main.c 函数中初始化 timer, 创建定时器及触发回调函数，并启动 TIMER1;

int main ( void )
{

    //...
    timers_init();

    ret_code_t err_code;
    err_code = app_timer_create(&bt_start_period_timer_id, APP_TIMER_MODE_REPEATED, bt_start_timeout_handler);
    APP_ERROR_CHECK(err_code);

    err_code = app_timer_create(&bt_cancel_period_timer_id, APP_TIMER_MODE_REPEATED, bt_cancel_timeout_handler);
    APP_ERROR_CHECK(err_code);

    app_timer_start( bt_start_period_timer_id, BT_START_PERIOD_TIMER_INTERVAL, NULL);

    //...

}

2. 定时器 TIMER1 回调函数, 开始蓝牙初始化和开始广播，并在函数中启动 TIMER2；

static void bt_start_timeout_handler(void * p_context) 
{ 
    UNUSED_PARAMETER(p_context);
    ret_code_t err_code;	

    err_code = app_timer_start( bt_cancel_period_timer_id, BT_CANCEL_PERIOD_TIMER_INTERVAL, NULL);
    APP_ERROR_CHECK(err_code);

    if ( m_conn_handle == BLE_CONN_HANDLE_INVALID )
    {
        advertising_init();	
        advertising_start_with_mode( BLE_ADV_MODE_FAST );		
    }
    //printf( "adv current after adv-start: %d \r\n",(&m_advertising)->adv_mode_current);	
}

3. 定时器 TIMER2 回调函数

static void bt_cancel_timeout_handler(void * p_context) 
{ 
		
    UNUSED_PARAMETER(p_context);
    ret_code_t err_code;

    advertising_start_with_mode( BLE_ADV_MODE_IDLE );
	//printf( "adv current before gap-disc: %d \r\n",(&m_advertising)->adv_mode_current );
    
    if ( m_conn_handle != BLE_CONN_HANDLE_INVALID )
    {
        err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
        APP_ERROR_CHECK(err_code);
    }
    // printf( "adv current after gap-disc: %d \r\n",(&m_advertising)->adv_mode_current );

    // 注：曾用 sd_ble_gap_adv_stop() 测试，主机未扫描时，程序正常，但主机扫描联结后，程序出错
    // 但未进一步测试，故在此备注说明
    // err_code = sd_ble_gap_adv_stop( m_advertising.adv_handle );
    // APP_ERROR_CHECK(err_code);		

    app_timer_stop( bt_cancel_timer_id );   
}

4. 广播初始化函数

/**@brief Function for initializing the Advertising functionality.*/ 
static void advertising_init(void)
{
    uint32_t                    err_code;
    ble_advertising_init_t      init;

    ble_advdata_manuf_data_t 	adv_manuf_data;
    uint8_array_t            	adv_manuf_data_array;
    uint8_t                  	adv_manuf_data_data[1];
    adv_manuf_data_data[0]      = 0x88;
	
    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;
    init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.srdata.uuids_complete.p_uuids  = m_adv_uuids;

    adv_manuf_data_array.p_data          = adv_manuf_data_data;
    adv_manuf_data_array.size            = sizeof(adv_manuf_data_data);
    adv_manuf_data.company_identifier    = 0x9876;
    adv_manuf_data.data                  = adv_manuf_data_array;
    init.advdata.p_manuf_specific_data   = &adv_manuf_data;	
	
    init.config.ble_adv_whitelist_enabled           = false;
    init.config.ble_adv_directed_high_duty_enabled  = false;
    init.config.ble_adv_directed_enabled            = false;	
    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.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);
}