BLE协议栈之Central事件慢慢谈

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BLE协议栈Central 工程中与广播连接建立的事件

最近在改写BLE协议栈，需要实现实时发现周边从设备，并建立连接，获取RSSI的功能，没什么难度，但着实将各个事件好好看了一遍。曾经看到一位大神说相同的任务使用事件触发方式，不同的任务使用消息传递方式。冥冥之中突然来了感觉~

BLE进行广播和建立连接的事件主要实现是在simpleBLECentralEventCB的回调函数中:

所有使用到的变量都在联合体gapCentralRoleEvent_t中：

typedef union{  gapEventHdr_t             gap;                //!< GAP_MSG_EVENT and status.  gapDeviceInitDoneEvent_t  initDone;           //!< GAP initialization done. 本机信息  gapDeviceInfoEvent_t deviceInfo;//!< Discovery device information event structure. 从机信息  gapDevDiscEvent_t      discCmpl;//!< Discovery complete event structure.从机信息（全部）  gapEstLinkReqEvent_t      linkCmpl;           //!< Link complete event structure.  gapLinkUpdateEvent_t      linkUpdate;         //!< Link update event structure.  gapTerminateLinkEvent_t   linkTerminate;      //!< Link terminated event structure.} gapCentralRoleEvent_t;      // central.h

1 板级初始化事件：GAP_DEVICE_INIT_DONE_EVENT

case GAP_DEVICE_INIT_DONE_EVENT:  // 初始化    //  是本机GAP层的初始化信息  在运行到GAPCentralRole_StartDevice函数被回调{      LCD_WRITE_STRING( bdAddr2Str( pEvent->initDone.devAddr ),  HAL_LCD_LINE_2 );}break;

详解：

作用：进行GAP层的初始化详解：/** * GAP_DEVICE_INIT_DONE_EVENT message format.  This message is sent to the * app when the Device Initialization is done [initiated by calling * GAP_DeviceInit()].    gap.h */typedef struct{  osal_event_hdr_t  hdr;              //!< GAP_MSG_EVENT and status  uint8 opcode;                       //!< GAP_DEVICE_INIT_DONE_EVENT  uint8 devAddr[B_ADDR_LEN];          //!< Device's BD_ADDR  本机的MAC地址  uint16 dataPktLen;                  //!< HC_LE_Data_Packet_Length    初始化长度为27   uint8 numDataPkts;                  //!< HC_Total_Num_LE_Data_Packets  初始化为4} gapDeviceInitDoneEvent_t;

2 搜索从机事件（每搜到一个从机进入一次）：GAP_DEVICE_INFO_EVENT

  case GAP_DEVICE_INFO_EVENT:    //过程量  从机的广播数据  搜索到之后添加到从机列表中      {        char temprssiarg[4]={0};        // if filtering device discovery results based on service UUID        if ( DEFAULT_DEV_DISC_BY_SVC_UUID == TRUE )        {          if ( simpleBLEFindSvcUuid( SIMPLEPROFILE_SERV_UUID,                                     pEvent->deviceInfo.pEvtData,                                     pEvent->deviceInfo.dataLen ) )          {             simpleBLEAddDeviceInfo( pEvent->deviceInfo.addr, pEvent->deviceInfo.addrType );                    }        }      }

作用：每搜索到一个从设备时，都会进入该事件，并使用simpleBLEAddDeviceInfo加入到扫描结果列表中，deviceInfo.addr中储存着当前正被扫描到从设备地址，扫描从机的数量（simpleBLEScanRes）在simpleBLEAddDeviceInfo中增加！

详解：

** * GAP_DEVICE_INFO_EVENT message format.  This message is sent to the * app during a Device Discovery Request, when a new advertisement or scan * response is received.  //gap.h */typedef struct{  osal_event_hdr_t  hdr;    //!< GAP_MSG_EVENT and status  uint8 opcode;             //!< GAP_DEVICE_INFO_EVENT  uint8 eventType; //!< Advertisement Type: @ref GAP_ADVERTISEMENT_TYPE_DEFINES  uint8 addrType;           //!< address type: @ref GAP_ADDR_TYPE_DEFINES  uint8 addr[B_ADDR_LEN];   //!< Address of the advertisement or SCAN_RSP  从机MAC地址  int8  rssi;                //!< Advertisement or SCAN_RSP RSSI    从机RSSI值  uint8 dataLen;            //!< Length (in bytes) of the data field (evtData)  uint8 *pEvtData;          //!< Data field of advertisement or SCAN_RSP} gapDeviceInfoEvent_t;

3 搜索从机事件（搜索完毕时进入一次）：GAP_DEVICE_DISCOVERY_EVENT

 case GAP_DEVICE_DISCOVERY_EVENT:       //结果量             // 搜索周边广播从机事件  显示搜索结果      {        // discovery complete        simpleBLEScanning = FALSE;        // if not filtering device discovery results based on service UUID        if ( DEFAULT_DEV_DISC_BY_SVC_UUID == FALSE )        {          // Copy results          simpleBLEScanRes = pEvent->discCmpl.numDevs;          osal_memcpy( simpleBLEDevList, pEvent->discCmpl.pDevList,                       (sizeof( gapDevRec_t ) * pEvent->discCmpl.numDevs) );        }              char temp_simpleBLEScanRes[10]="Find :  \n";                FineDeviceNum=FindDeviceNum=simpleBLEScanRes;//***************************************************************** 扫描的数量                 temp_simpleBLEScanRes[8] = simpleBLEScanRes+'0';                 Uart0Send_String(temp_simpleBLEScanRes,10);//***********************************                /******************************************************************************************************/        // initialize scan index to last device        simpleBLEScanIdx = simpleBLEScanRes;        IsPeriodicStart=1;                  }      break;

作用：程序运行到这一步可以知道当前有多少个已经被扫描到的从设备，且它们的地址被保存到simpleBLEDevList里。

搜索结果列表 // Scan result list

static gapDevRec_t simpleBLEDevList[DEFAULT_MAX_SCAN_RES]; // 扫描结果列表

详解：

/** * Type of device discovery (Scan) to perform. */typedef struct{  uint8 eventType;  //!< Indicates advertising event type used by the advertiser: @ref GAP_ADVERTISEMENT_TYPE_DEFINES  uint8 addrType;         //!< Address Type: @ref GAP_ADDR_TYPE_DEFINES  uint8 addr[B_ADDR_LEN]; //!< Device's Address  // 储存着当前搜索到的设备地址  最大可见扫描数量8} gapDevRec_t;        搜索结果结构体/** * GAP_DEVICE_DISCOVERY_EVENT message format. This message is sent to the * Application after a scan is performed. */typedef struct{  osal_event_hdr_t  hdr; //!< GAP_MSG_EVENT and status  uint8 opcode;          //!< GAP_DEVICE_DISCOVERY_EVENT  uint8 numDevs;         //!< Number of devices found during scan  gapDevRec_t *pDevList; //!< array of device records} gapDevDiscEvent_t;     搜索结果事件结构体

Note：需要知道一个从设备的RSSI值，只需知道从设备的MAC地址信息在simpleBLEDevList中即可！

4 连接建立事件：GAP_LINK_ESTABLISHED_EVENT

本事件里开起一个定时器，事件连接超时断开！

  case GAP_LINK_ESTABLISHED_EVENT:      {        if ( pEvent->gap.hdr.status == SUCCESS )        {                    simpleBLEState = BLE_STATE_CONNECTED;          simpleBLEConnHandle = pEvent->linkCmpl.connectionHandle;          simpleBLEProcedureInProgress = TRUE;              // If service discovery not performed initiate service discovery          if ( simpleBLECharHdl == 0 )          {            osal_start_timerEx( simpleBLETaskId, START_DISCOVERY_EVT, DEFAULT_SVC_DISCOVERY_DELAY );          }      //    SerialPrintString("Connected: ");         // Uart0Send_String( bdAddr2Str( pEvent->linkCmpl.devAddr ), sizeof(bdAddr2Str( pEvent->linkCmpl.devAddr )));         // for(int i=0;i<10000;i++);          for(int i=0;i<10000;i++);          LCD_WRITE_STRING( bdAddr2Str( pEvent->linkCmpl.devAddr ), HAL_LCD_LINE_2 );           for(int i=0;i<10000;i++);       // Uart0Send_String("12222",5);          //LCD_WRITE_STRING( "Connected", HAL_LCD_LINE_1 );    /***********   2015年1月8日 不间断的搜寻周围的从设备 ************** 建立连接后读取当前的RSSI 值***********************************************************************************************/                if ( simpleBLEState == BLE_STATE_CONNECTED )     {       if ( !simpleBLERssi )       {        simpleBLERssi = TRUE;        GAPCentralRole_StartRssi( simpleBLEConnHandle, DEFAULT_RSSI_PERIOD );       }       else       {        simpleBLERssi = FALSE;        GAPCentralRole_CancelRssi( simpleBLEConnHandle );                LCD_WRITE_STRING( "RSSI Cancelled", HAL_LCD_LINE_1 );         // SerialPrintString("RSSI Cancelled\r\n");       }     }    /****************************************************************************************************************/         }        else        {          simpleBLEState = BLE_STATE_IDLE;          simpleBLEConnHandle = GAP_CONNHANDLE_INIT;          simpleBLERssi = FALSE;          simpleBLEDiscState = BLE_DISC_STATE_IDLE;                    LCD_WRITE_STRING( "Connect Failed", HAL_LCD_LINE_1 );       //   SerialPrintString("Connect Failed: ");          LCD_WRITE_STRING_VALUE( "Reason:", pEvent->gap.hdr.status, 10, HAL_LCD_LINE_2 );                             GAPCentralRole_CancelRssi( simpleBLEConnHandle );                /***********   2015年1月8日 不间断的搜寻周围的从设备 ************** 连接错误 主机从新进行搜索***********************************************************************************************/                           simpleBLEScanning = TRUE;           simpleBLEScanRes = 0;        LCD_WRITE_STRING( "Discovering...", HAL_LCD_LINE_1 );        LCD_WRITE_STRING( "", HAL_LCD_LINE_2 );        GAPCentralRole_StartDiscovery( DEFAULT_DISCOVERY_MODE,                                       DEFAULT_DISCOVERY_ACTIVE_SCAN,                                       DEFAULT_DISCOVERY_WHITE_LIST );        /*****************************************************************************************************/       //   SerialPrintValue("Reason:",  pEvent->gap.hdr.status,10);        }      }      break;

详解：/** * GAP_LINK_ESTABLISHED_EVENT message format.  This message is sent to the app * when the link request is complete.<BR> * <BR> * For an Observer, this message is sent to complete the Establish Link Request.<BR> * For a Peripheral, this message is sent to indicate that a link has been created. */typedef struct{  osal_event_hdr_t  hdr;     //!< GAP_MSG_EVENT and status  uint8 opcode;              //!< GAP_LINK_ESTABLISHED_EVENT  uint8 devAddrType;         //!< Device address type: @ref GAP_ADDR_TYPE_DEFINES  uint8 devAddr[B_ADDR_LEN]; //!< Device address of link  uint16 connectionHandle;   //!< Connection Handle from controller used to ref the device  uint16 connInterval;       //!< Connection Interval  uint16 connLatency;        //!< Conenction Latency  uint16 connTimeout;        //!< Connection Timeout  uint8 clockAccuracy;       //!< Clock Accuracy} gapEstLinkReqEvent_t;

5 连接超时事件 : GAP_LINK_TERMINATED_EVENT

  case GAP_LINK_TERMINATED_EVENT:      {        simpleBLEState = BLE_STATE_IDLE;        simpleBLEConnHandle = GAP_CONNHANDLE_INIT;        simpleBLERssi = FALSE;        simpleBLEDiscState = BLE_DISC_STATE_IDLE;        simpleBLECharHdl = 0;        simpleBLEProcedureInProgress = FALSE;                  LCD_WRITE_STRING( "Disconnected", HAL_LCD_LINE_1 );     //   SerialPrintString("Disconnected: ");        LCD_WRITE_STRING_VALUE( "Reason:", pEvent->linkTerminate.reason,                                10, HAL_LCD_LINE_2 );                   // SerialPrintValue("Reason:",  pEvent->linkTerminate.reason,10);      }

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