nrf51822 --- 广播间隔

1.目的

   设置广播间隔，已达到一个功耗最佳的状态

2.分析

   广播间隔，指每次蓝牙广播之间的间隔，间隔越大功耗越低，间隔越小功耗越大

3.平台：

协议栈版本：SDK10.0.0

编译软件：keil 5.14

硬件平台：nrf51822最小系统

例子：SDK 10.0.0\examples\ble_peripheral\ble_app_uart\pca10028\s110\arm4

4.步骤

在main.c

#define APP_ADV_INTERVAL                64                                          /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */
#define APP_ADV_TIMEOUT_IN_SECONDS      180                                         /**< The advertising timeout (in units of seconds). */

static void advertising_init(void)
{
    uint32_t      err_code;
    ble_advdata_t advdata;
    ble_advdata_t scanrsp;

    // Build advertising data struct to pass into @ref ble_advertising_init.
    memset(&advdata, 0, sizeof(advdata));
    advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    advdata.include_appearance = false;
    advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;

    memset(&scanrsp, 0, sizeof(scanrsp));
    scanrsp.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    scanrsp.uuids_complete.p_uuids  = m_adv_uuids;

    ble_adv_modes_config_t options = {0};
    options.ble_adv_fast_enabled  = BLE_ADV_FAST_ENABLED;
    options.ble_adv_fast_interval =<strong> </strong>APP_ADV_INTERVAL<strong>;</strong>
    options.ble_adv_fast_timeout  = APP_ADV_TIMEOUT_IN_SECONDS<strong>;</strong>
 
		
    err_code = ble_advertising_init(&advdata, &scanrsp, &options, on_adv_evt, NULL);
    APP_ERROR_CHECK(err_code);
}

APP_ADV_INTERVAL ：是广播的间隔设置,单位为0.625ms，设置表示广播间隔大，功耗低，反正，相反。

APP_ADV_TIMEOUT_IN_SECONDS ：广播超时时间，单位为s ，这个参数与

   advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;

这个参数有关系，设置为BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE模式的时候，

表示广播APP_ADV_TIMEOUT_IN_SECONDS 秒，系统会产生蓝牙超时时间，并且不再广播

<pre name="code" class="cpp">static void on_ble_evt(ble_evt_t * p_ble_evt)
{
    uint32_t                         err_code;
    
    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;

            break;
            
        case BLE_GAP_EVT_DISCONNECTED:
            err_code = bsp_indication_set(BSP_INDICATE_IDLE);
            APP_ERROR_CHECK(err_code);
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            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_GAP_EVT_TIMEOUT :
	{
		//这里会产生蓝牙超时事件		 
	}
	break;<strong>  </strong>
        default;
            // No implementation needed.
            break;
    }
}

 在一般的应该中都不许关闭蓝牙，蓝牙要一直广播:

设置如下:

  

#define APP_ADV_TIMEOUT_IN_SECONDS     <strong> </strong>0                                        /**< The advertising timeout (in units of seconds). */

static void advertising_init(void)
{
    uint32_t      err_code;
    ble_advdata_t advdata;
    ble_advdata_t scanrsp;

    // Build advertising data struct to pass into @ref ble_advertising_init.
    memset(&advdata, 0, sizeof(advdata));
    advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    advdata.include_appearance = false;
    advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;

    memset(&scanrsp, 0, sizeof(scanrsp));
    scanrsp.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    scanrsp.uuids_complete.p_uuids  = m_adv_uuids;

    ble_adv_modes_config_t options = {0};
    options.ble_adv_fast_enabled  = BLE_ADV_FAST_ENABLED;
    options.ble_adv_fast_interval = APP_ADV_INTERVAL;
    options.ble_adv_fast_timeout  = APP_ADV_TIMEOUT_IN_SECONDS;
 
		
    err_code = ble_advertising_init(&advdata, &scanrsp, &options, on_adv_evt, NULL);
    APP_ERROR_CHECK(err_code);
}

#define  APP_ADV_INTERVAL                0              

advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;

这样蓝牙就会永久广播，永远不会停止。