原文網址：http://m.blog.csdn.net/blog/chiooo/43985401

BLE 學習記錄

ANROID BLE 開發，基于 bluetoothlegatt 分析

mBluetoothAdapter = mBluetoothManager.getAdapter(); 得到 手機上藍牙主機的適配器 mBluetoothAdapter

public boolean initialize() {?
// For API level 18 and above, get a reference to BluetoothAdapter through?
// BluetoothManager.?
if (mBluetoothManager == null) {?
mBluetoothManager = (BluetoothManager) mContext.getSystemService(Context.BLUETOOTH_SERVICE);?
if (mBluetoothManager == null) {?
Log.e(TAG, “Unable to initialize BluetoothManager.”);?
return false;?
}?
}

mBluetoothAdapter = mBluetoothManager.getAdapter(); if (mBluetoothAdapter == null) {Log.e(TAG, "Unable to obtain a BluetoothAdapter.");return false; }return true;

}

2.獲得mBluetoothGatt，注冊回調

* Connects to the GATT server hosted on the Bluetooth LE device.** @param address The device address of the destination device.** @return Return true if the connection is initiated successfully. The connection result* is reported asynchronously through the* {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}* callback.public boolean connect(final String address) {if (mBluetoothAdapter == null || address == null) {Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");return false;}// Previously connected device. Try to reconnect.if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress)&& mBluetoothGatt != null) {Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");if (mBluetoothGatt.connect()) {return true;} else {return false;}}final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address); 得到bluetoothdeviceif (device == null) {Log.w(TAG, "Device not found. Unable to connect.");return false;}// We want to directly connect to the device, so we are setting the autoConnect// parameter to false.mBluetoothGatt = device.connectGatt(mContext, false, mGattCallback);//bluetoothdevice得到mBluetoothGatt 傳進去的是 BluetoothGattCallback，從名字看就是回調。Log.d(TAG, "Trying to create a new connection.");mBluetoothDeviceAddress = address;return true; }

3.讀寫BluetoothGattCharacteristic，使能notification

mBluetoothGatt.readCharacteristic(characteristic); 讀 mBluetoothGatt.writeCharacteristic(characteristic); 寫* Enables or disables notification on a give characteristic.** @param characteristic Characteristic to act on.* @param enabled If true, enable notification. False otherwise.public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,boolean enabled) {if (mBluetoothAdapter == null || mBluetoothGatt == null) {Log.w(TAG, "BluetoothAdapter not initialized");return;}mBluetoothGatt.setCharacteristicNotification(characteristic, enabled); }向下寫數據： //設置數據內容gattCharacteristic.setValue("send data->");//往藍牙模塊寫入數據mBLE.writeCharacteristic(gattCharacteristic); 讀數據：if(gattCharacteristic.getUuid().toString().equals(UUID_KEY_DATA)){ //測試讀取當前Characteristic數據，會觸發mOnDataAvailable.onCharacteristicRead()mHandler.postDelayed(new Runnable() {@Overridepublic void run() {mBLE.readCharacteristic(gattCharacteristic);}}, 500);//接受Characteristic被寫的通知,收到藍牙模塊的數據后會觸發mOnDataAvailable.onCharacteristicWrite()mBLE.setCharacteristicNotification(gattCharacteristic, true);

4.得到 supported services

* Retrieves a list of supported GATT services on the connected device. This should be* invoked only after {@code BluetoothGatt#discoverServices()} completes successfully.** @return A {@code List} of supported services.public List<BluetoothGattService> getSupportedGattServices() {if (mBluetoothGatt == null) return null;return mBluetoothGatt.getServices(); }

5.關系

BluetoothGatt 代表一個連接，里面包含一個或者多個 BluetoothGattService ， 而每個BluetoothGattService 包含多個BluetoothGattCharacteristic ， 一個 BluetoothGattCharacteristic 里面可能包含0個或者多個 BluetoothGattDescriptor

6.BLE 設備端LOG?
條件：?
主機端：BLEGATTLE 參考程序，?
設備端： NODIC官方BLE UART 程序

串口端LOG：

main start trace uart_init ..\main.c:leds_init:137> enter_now ..\main.c:timers_init:149> enter_now ..\main.c:ble_stack_init:457> enter_now ..\main.c:gap_params_init:166> enter_now Start... ..\main.c:advertising_start:331> enter_now ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:16// connect event p_ble_evt->header.evt_id:16 p_ble_evt->header.evt_id:16 ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:20 p_ble_evt->header.evt_id:20// BLE_GAP_EVT_SEC_INFO_REQUEST p_ble_evt->header.evt_id:20 ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:19 p_ble_evt->header.evt_id:19// BLE_GAP_EVT_SEC_PARAMS_REQUEST p_ble_evt->header.evt_id:19 ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:80 // write event p_ble_evt->header.evt_id:80 p_ble_evt->header.evt_id:80 ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:80 // write event p_ble_evt->header.evt_id:80 ..\main.c:nus_data_handler:224> enter_now send data-> // received data p_ble_evt->header.evt_id:80 // write event ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:24// BLE_GAP_EVT_AUTH_STATUS p_ble_evt->header.evt_id:24 p_ble_evt->header.evt_id:24 ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:23 // BLE_GAP_EVT_AUTH_KEY_REQUEST p_ble_evt->header.evt_id:23 p_ble_evt->header.evt_id:23 ..\main.c:ble_evt_dispatch:442> enter_now p_ble_evt->header.evt_id:18 ..\main.c:on_conn_params_evt:279> enter_now p_ble_evt->header.evt_id:18 // BLE_GAP_EVT_CONN_PARAM_UPDATE p_ble_evt->header.evt_id:18

7.BLE連接參數

#define MIN_CONN_INTERVALMSEC_TO_UNITS(500, UNIT_1_25_MS) /**< Minimum acceptable connection interval (0.5 seconds). */6~3200, 就是說7.5MS~ 4S, 1.25MS單位。連接時間間隔。 #define MAX_CONN_INTERVALMSEC_TO_UNITS(1000, UNIT_1_25_MS)/**< Maximum acceptable connection interval (1 second). */ #define SLAVE_LATENCY0 跳過連接事件/**< Slave latency. */ #define CONN_SUP_TIMEOUT MSEC_TO_UNITS(4000, UNIT_10_MS) /**< Connection supervisory timeout (4 seconds). */ 管理超時，如果超過此時間沒有連接成功事件，則認為是連接丟失。

實驗驗證：

#define MIN_CONN_INTERVAL 16 /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */ #define MAX_CONN_INTERVAL 500 /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */ #define SLAVE_LATENCY 0 /**< slave latency. */ #define CONN_SUP_TIMEOUT 2000 /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */ #define FIRST_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(20000, APP_TIMER_PRESCALER) /**< 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, APP_TIMER_PRESCALER) /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */ #define MAX_CONN_PARAMS_UPDATE_COUNT 3

測試記錄：

當APP剛連接上時，這之間用得連接參數是由手機端決定的，經過FIRST_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS 后，手機端會發新的參數過來，我測試過的，手機端都是MAX_CONN_INTERVAL 來決定，SLAVE_LATENCY 不管我改成多少，下發的都是0。

網絡上討論

對于IOS設備來說, 蘋果設置了一系列規定, 不允許從設備的配置超出這些范圍. 其他主設備來說目前還沒有聽說有什么具體范圍設定. Android設備目前google也還沒有明確規定. 所以換句話說, 只要符合主設備的要求, 從設備是可以在主設備規定的范圍內請求主設備對connection interval進行改變的.

你通過GAP_SetParamValue()只是設置了參數, 最后是需要通過發送到主設備那里去請求修改的. 所以這里不正確.請參考 GAPRole_SetParameter( GAPROLE_PARAM_UPDATE_ENABLE, ..) 函數的做法.

你可以通過packet sniffer抓包, 在時間戳上很清楚能看到connection interval. 或者你也可以自己加點代碼, 從程序里面獲取, 或者以notify方式發給主設備, 從主設備看, 總之, 方法很多哈.?
另外附上蘋果對connection interval的要求, 其實還有其他的連接參數要求, 比如slave latency, supervision timeout, 如果不滿足這些, IOS設備會拒絕.

The connection parameter request may be rejected if it does not comply with all of these rules:?
Interval Max * (Slave Latency + 1) ≤ 2 seconds?
Interval Min ≥ 20 ms?
Interval Min + 20 ms ≤ Interval Max?
Slave Latency ≤ 4?
connSupervisionTimeout ≤ 6 seconds?
Interval Max * (Slave Latency + 1) * 3 < connSupervisionTimeout

8.從設備怎么主動斷開連接

你可以直接調用 GAPRole_TerminateConnection() 來主動斷開連接。?
那個函數調用后，連接順利斷開后會收到 GAP_LINK_TERMINATED_EVENT 事件。?
在這個事件之后，你再重新啟動廣播，即可

轉載于:https://www.cnblogs.com/wi100sh/p/4422686.html

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