代碼解析

1. int main(void)

int main(void)
{
  /* Initialize hardware */
  HAL_BOARD_INIT();//初始化時鐘和使能緩存預取模式

  // Initialize board I/O
  InitBoard( OB_COLD );//冷啟動，關閉了led燈與中斷，避免接下來的各種初始化受干擾

  /* Initialze the HAL driver */
  HalDriverInit();//各種驅動的初始化、如按鍵、lcd、adc、usb、uart等8

  /* Initialize NV system */
  osal_snv_init();//snv 內部用于保存配對數據或你的用戶自定義數據的一段flash，4kB空間

  /* Initialize LL */  
  /* Initialize the operating system */
  osal_init_system();//oasl 操作系統初始化, 包含內存分配、消息隊列、定時器、電源管理和任務等

  /* Enable interrupts */
  HAL_ENABLE_INTERRUPTS();// 開啟全局中斷

  // Final board initialization
  InitBoard( OB_READY );  //設置標志標示系統初始化完畢
}

1. osal_init_system()

uint8 osal_init_system( void )
{
  // Initialize the Memory Allocation System
  osal_mem_init();//初始化內存分配系統

  // Initialize the message queue
  osal_qHead = NULL;//初始化消息隊列

  // Initialize the timers
  osalTimerInit();//初始化定時器

  // Initialize the Power Management System
  osal_pwrmgr_init();//初始化電源管理系統

  // Initialize the system tasks.
  osalInitTasks();//初始化系統任務， 這一個任務初始花非常關鍵

  // Setup efficient search for the first free block of heap.
  osal_mem_kick();
 
  return ( SUCCESS );
}

1. osalInitTasks()

void osalInitTasks( void )
{
  /* L2CAP Task */
  L2CAP_Init( taskID++ );

  /* GAP Task */
  GAP_Init( taskID++ );

  /* GATT Task */
  GATT_Init( taskID++ );

  /* SM Task */
  SM_Init( taskID++ );

  /* Profiles */
  GAPRole_Init( taskID++ );    //鏈路角色初始化
  GAPBondMgr_Init( taskID++ );  //鏈路綁定初始化
  GATTServApp_Init( taskID++ );
  /* Application */
  SimpleBLEPeripheral_Init( taskID );
}

1. GAPRole_Init( taskID++ )

void GAPRole_Init( uint8 task_id )
{
  gapRole_TaskID = task_id;  //定義任務地址

  gapRole_state = GAPROLE_INIT;  //鏈路狀態設置為GAPROLE_INIT
  gapRole_ConnectionHandle = INVALID_CONNHANDLE;  //設置鏈路連接句柄為0xFFFF
  GAP_RegisterForHCIMsgs( gapRole_TaskID );//注冊控制接口的任務ID

  // Initialize the Profile Advertising and Connection Parameters
  gapRole_profileRole = GAP_PROFILE_PERIPHERAL;  //鏈路配置角色為從機
  VOID osal_memset( gapRole_IRK, 0, KEYLEN );    //密鑰緩沖器清零
  VOID osal_memset( gapRole_SRK, 0, KEYLEN );
  gapRole_signCounter = 0;                       //密鑰計數標志位清零
  gapRole_AdvEventType = GAP_ADTYPE_ADV_IND; //廣播類型為可連接無定向廣播
  gapRole_AdvDirectType = ADDRTYPE_PUBLIC; //廣播方式為通過廣播（可被發現掃描連接）
  gapRole_AdvChanMap = GAP_ADVCHAN_ALL ;  //廣播所有通道37、38、39
  gapRole_AdvFilterPolicy = GAP_FILTER_POLICY_ALL;  //允許掃描，允許連接
  // Restore Items from NV
  VOID osal_snv_read( BLE_NVID_IRK, KEYLEN, gapRole_IRK ); //讀出存儲的密鑰和密鑰計數標志位
  VOID osal_snv_read( BLE_NVID_CSRK, KEYLEN, gapRole_SRK );

  VOID osal_snv_read( BLE_NVID_SIGNCOUNTER, sizeof( uint32 ), &gapRole_signCounter );
}	

1. SimpleBLEPeripheral_Init

//初始化完成后

void SimpleBLEPeripheral_Init( uint8 task_id )
{
	osal_set_event( simpleBLEPeripheral_TaskID, SBP_START_DEVICE_EVT );              //啟動設備開始事件
}

1. SimpleBLEPeripheral_ProcessEvent

uint16 SimpleBLEPeripheral_ProcessEvent( uint8 task_id, uint16 events )
{     
  if ( events & SBP_START_DEVICE_EVT )// 初始化后就執行這個啦
      {              
            // Start the Device
            VOID GAPRole_StartDevice( &simpleBLEPeripheral_PeripheralCBs ); //配置鏈路事件通知回調函數
        
            // Start Bond Manager
            VOID GAPBondMgr_Register( &simpleBLEPeripheral_BondMgrCBs ); //配置配對消息回調函數
            
            // Set timer for first periodic event
            osal_start_timerEx( simpleBLEPeripheral_TaskID, POWER_DETECT_EVT, DetectPowerPeriod );   
      
            return ( events ^ SBP_START_DEVICE_EVT );
      }
}

1. GAPRole_StartDevice

Status_t GAPRole_StartDevice( gapRolesCBs_t *pAppCallbacks )
{
  if ( gapRole_state == GAPROLE_INIT ) //如果鏈路狀態是初始化狀態
  {
    // Clear all of the Application callbacks
    if ( pAppCallbacks )
    {
      pGapRoles_AppCGs = pAppCallbacks;//設置回調函數
    }

    // Start the GAP
    gapRole_SetupGAP();//開始建立鏈路
    return ( SUCCESS );
  }
  else     //否則返回已經在請求模式狀態
  {
    return ( bleAlreadyInRequestedMode );
  }
}

1. gapRole_SetupGAP

static void gapRole_SetupGAP( void )
{
  VOID GAP_DeviceInit( gapRole_TaskID,
          gapRole_profileRole, 0,
          gapRole_IRK, gapRole_SRK,
          &gapRole_signCounter );
}

1. GAP_DeviceInit

bStatus_t GAP_DeviceInit(  uint8 taskID,
                           uint8 profileRole,
                           uint8 maxScanResponses,
                           uint8 *pIRK,
                           uint8 *pSRK,
                           uint32 *pSignCounter )
{
    // Setup the device configuration parameters
stat = GAP_ParamsInit( taskID, profileRole );  //設置設備配置參數
 
    #if ( HOST_CONFIG & ( CENTRAL_CFG | PERIPHERAL_CFG ) )
    {
      GAP_SecParamsInit( pIRK, pSRK, pSignCounter );
    }
#endif 
#if ( HOST_CONFIG & ( PERIPHERAL_CFG | BROADCASTER_CFG ) )
{
   // Initialize GAP Peripheral Device Manager
   VOID GAP_PeriDevMgrInit();  //初始化從機設備管理
   #if ( HOST_CONFIG & PERIPHERAL_CFG )
   {
     // Initialize SM Responder
     VOID SM_ResponderInit();  //回應者初始化
   }
   #endif
 }
 #endif
}

1. 當GAP_DeviceInit初始化完成后，將產生GAP_DEVICE_INIT_DONE_EVENT事件； uint16 GAPRole_ProcessEvent( uint8 task_id, uint16 events ) //鏈路處理事件

2. static void gapRole_ProcessOSALMsg( osal_event_hdr_t *pMsg ) //鏈路系統消息事件

3. gapRole_ProcessGAPMsg

static void gapRole_ProcessGAPMsg( gapEventHdr_t *pMsg )  //鏈路處理連接消息
{
  uint8 notify = FALSE;   // State changed notify the app? (default no)

  switch ( pMsg->opcode )
  {
      case GAP_DEVICE_INIT_DONE_EVENT: //當GAP_DeviceInit初始化完成后，將產生此事件
      {
        gapDeviceInitDoneEvent_t *pPkt = (gapDeviceInitDoneEvent_t *)pMsg;
        bStatus_t stat = pPkt->hdr.status;

        if ( stat == SUCCESS )
        {
          // Save off the generated keys
          VOID osal_snv_write( BLE_NVID_IRK, KEYLEN, gapRole_IRK );//保存生成的密鑰
          VOID osal_snv_write( BLE_NVID_CSRK, KEYLEN, gapRole_SRK );


          // Save off the information
          VOID osal_memcpy( gapRole_bdAddr, pPkt->devAddr, B_ADDR_LEN );//保存設備地址
          gapRole_state = GAPROLE_STARTED;  //鏈路開始

          // Update the advertising data
          stat = GAP_UpdateAdvertisingData( gapRole_TaskID,//更新廣播數據
                              TRUE, gapRole_AdvertDataLen, gapRole_AdvertData );
        }
            notify = TRUE;  //通知回調函數鏈路的狀態
      }

      break;
      if ( notify == TRUE )
      {
          // Notify the application with the new state change
          if ( pGapRoles_AppCGs && pGapRoles_AppCGs->pfnStateChange ) //判斷是否設置了回調函數
          {
               pGapRoles_AppCGs->pfnStateChange( gapRole_state );//調用設置的回調函數，通知gapRole_state當前狀態
          }
      }
}

1. stat=GAP_UpdateAdvertisingData( gapRole_TaskID,TRUE, gapRole_AdvertDataLen, gapRole_AdvertData );//更新廣播數據后，將產生GAP_ADV_DATA_UPDATE_DONE_EVENT事件；

2. gapRole_ProcessGAPMsg

static void gapRole_ProcessGAPMsg( gapEventHdr_t *pMsg )  //鏈路處理連接消息
{
  uint8 notify = FALSE;   // State changed notify the app? (default no)
  switch ( pMsg->opcode )
  {
      case GAP_ADV_DATA_UPDATE_DONE_EVENT:
      {
        gapAdvDataUpdateEvent_t *pPkt = (gapAdvDataUpdateEvent_t *)pMsg;
        if ( pPkt->hdr.status == SUCCESS )
        {
          if ( pPkt->adType )
          {
            // Setup the Response Data
            pPkt->hdr.status = GAP_UpdateAdvertisingData( gapRole_TaskID,
                              FALSE, gapRole_ScanRspDataLen, gapRole_ScanRspData );//更新掃描回應數據
          }
          else
          {
            // Start advertising
            VOID osal_set_event( gapRole_TaskID, START_ADVERTISING_EVT );  //啟動廣播事件
          }
        }
        if ( pPkt->hdr.status != SUCCESS ) //如果不成功將通知回調函數，否則不通知
        {
          // Set into Error state
          gapRole_state = GAPROLE_ERROR;
          notify = TRUE;
        }
      }
      break;

1. gapRole_ProcessGAPMsg

static void gapRole_ProcessGAPMsg( gapEventHdr_t *pMsg )  //鏈路處理連接消息
{
  uint8 notify = FALSE;   // State changed notify the app? (default no)
  switch ( pMsg->opcode )
  {
      case GAP_ADV_DATA_UPDATE_DONE_EVENT:
      {
        gapAdvDataUpdateEvent_t *pPkt = (gapAdvDataUpdateEvent_t *)pMsg;

        if ( pPkt->hdr.status == SUCCESS )
        {
          if ( pPkt->adType )
          {
            // Setup the Response Data
            pPkt->hdr.status = GAP_UpdateAdvertisingData( gapRole_TaskID,
                              FALSE, gapRole_ScanRspDataLen, gapRole_ScanRspData );//更新掃描回應數據
          }
          else
          {
            // Start advertising
           VOID osal_set_event( gapRole_TaskID, START_ADVERTISING_EVT );  //啟動廣播事件
          }
        }

        if ( pPkt->hdr.status != SUCCESS ) //如果不成功將通知回調函數，否則不通知
        {
          // Set into Error state
          gapRole_state = GAPROLE_ERROR;
          notify = TRUE;
        }
      }
      break;

1. 執行廣播事件

uint16 GAPRole_ProcessEvent( uint8 task_id, uint16 events )
{
  VOID task_id; // OSAL required parameter that isn't used in this function

  if ( events & START_ADVERTISING_EVT )
  {
    if ( gapRole_AdvEnabled )
    {
      gapAdvertisingParams_t params;
 
      // Setup advertisement parameters
      params.eventType = gapRole_AdvEventType; //GAP_ADTYPE_ADV_IND; 廣播類型為可連接無定向廣播
      params.initiatorAddrType = gapRole_AdvDirectType; //ADDRTYPE_PUBLIC; 廣播方式為通用廣播
      VOID osal_memcpy( params.initiatorAddr, gapRole_AdvDirectAddr, B_ADDR_LEN ); //發起者地址配置
      params.channelMap = gapRole_AdvChanMap;  //廣播通道配置：廣播所有通道37、38、39
      params.filterPolicy = gapRole_AdvFilterPolicy;//過濾策略GAP_FILTER_POLICY_ALL;允許掃描，允許連接
 
      if ( GAP_MakeDiscoverable( gapRole_TaskID, ¶ms ) != SUCCESS ) //配置廣播參數，并產生一個GAP_MakeDiscoverable      消息事件
      {
       gapRole_state = GAPROLE_ERROR;//如果不成功將通知回調函數-鏈路錯誤   

        // Notify the application with the new state change
        if ( pGapRoles_AppCGs && pGapRoles_AppCGs->pfnStateChange )
        {
          pGapRoles_AppCGs->pfnStateChange( gapRole_state );
        }
      }
    }
    return ( events ^ START_ADVERTISING_EVT );
  }

1. 處理GAP_MakeDiscoverable消息事件

 static void gapRole_ProcessGAPMsg( gapEventHdr_t *pMsg )  //鏈路處理連接消息
{
  uint8 notify = FALSE;   // State changed notify the app? (default no)
 
  switch ( pMsg->opcode )
  {
      case GAP_MAKE_DISCOVERABLE_DONE_EVENT:  //使能可被發現完成事件即開始廣播了
      case GAP_END_DISCOVERABLE_DONE_EVENT:   //結束可被發現完成事件即停止廣播了
      {
        gapMakeDiscoverableRspEvent_t *pPkt = (gapMakeDiscoverableRspEvent_t *)pMsg;
        if ( pPkt->hdr.status == SUCCESS )
        {
          if ( pMsg->opcode == GAP_MAKE_DISCOVERABLE_DONE_EVENT )
          {
           gapRole_state = GAPROLE_ADVERTISING;  //設置當前鏈路狀態
          }
          else // GAP_END_DISCOVERABLE_DONE_EVENT//結束可被發現完成事件即停止廣播了
          {
            if ( gapRole_AdvertOffTime != 0 )  //如果gapRole_AdvertOffTime等于0，將不再廣播，否則啟動定時廣播件
            {
              if ( ( gapRole_AdvEnabled ) )//如果使能廣播
              {
            VOID osal_start_timerEx( gapRole_TaskID, START_ADVERTISING_EVT, gapRole_AdvertOffTime );//啟動周期廣播事件
              }
            }
            else
            {
              // Since gapRole_AdvertOffTime is set to 0, the device should not
              // automatically become discoverable again after a period of time.
              // Set enabler to FALSE; device will become discoverable again when
              // this value gets set to TRUE
              gapRole_AdvEnabled = FALSE;
            }

            // In the Advertising Off period
            gapRole_state = GAPROLE_WAITING;//如果GAP_END_DISCOVERABLE_DONE_EVENT，鏈路當前狀態為等待狀態
          }
        }
        else
        {
          gapRole_state = GAPROLE_ERROR;
        }
        notify = TRUE;//通知回調函數
      }
      break;

  if ( notify == TRUE )
  {
      // Notify the application with the new state change
      if ( pGapRoles_AppCGs && pGapRoles_AppCGs->pfnStateChange ) //判斷是否設置了回調函數
      {
           pGapRoles_AppCGs->pfnStateChange( gapRole_state );//調用設置的回調函數，通知gapRole_state當前狀態
      }
  }

1. 這時候底層已經使能硬件在廣播了，要么廣播超時產生一個GAP_END_DISCOVERABLE_DONE_EVENT消息，要么被連接事件 GAP_LINK_ESTABLISHED_EVENT；

2. 廣播超時產生一個GAP_END_DISCOVERABLE_DONE_EVENT消息

static void gapRole_ProcessGAPMsg( gapEventHdr_t *pMsg )  //鏈路處理連接消息
{
  uint8 notify = FALSE;   // State changed notify the app? (default no)
  switch ( pMsg->opcode )
  {  
  case GAP_MAKE_DISCOVERABLE_DONE_EVENT:  //使能可被發現完成事件即開始廣播了
      case GAP_END_DISCOVERABLE_DONE_EVENT:   //結束可被發現完成事件即停止廣播了
      {
        gapMakeDiscoverableRspEvent_t *pPkt = (gapMakeDiscoverableRspEvent_t *)pMsg;

        if ( pPkt->hdr.status == SUCCESS )
        {
          if ( pMsg->opcode == GAP_MAKE_DISCOVERABLE_DONE_EVENT )
          {
            gapRole_state = GAPROLE_ADVERTISING;  //設置當前鏈路狀態
          }
          else // GAP_END_DISCOVERABLE_DONE_EVENT//結束可被發現完成事件即停止廣播了
          {
            if ( gapRole_AdvertOffTime != 0 )  //如果gapRole_AdvertOffTime不等于0，啟動定時廣播事件，否則將關閉廣播
            {
              if ( ( gapRole_AdvEnabled ) )//如果使能廣播
              {
            VOID osal_start_timerEx( gapRole_TaskID, START_ADVERTISING_EVT, gapRole_AdvertOffTime );//啟動周期廣播事件
              }
            }
            else
            {
              // Since gapRole_AdvertOffTime is set to 0, the device should not
            // automatically become discoverable again after a period of time.
              // Set enabler to FALSE; device will become discoverable again when
              // this value gets set to TRUE
              gapRole_AdvEnabled = FALSE; //關閉廣播
            }
           // In the Advertising Off period
             gapRole_state = GAPROLE_WAITING;//如果GAP_END_DISCOVERABLE_DONE_EVENT，鏈路當前狀態為等待狀態，或不再廣播或等待周期廣播          
            }
        }
        else
        {
          gapRole_state = GAPROLE_ERROR;
        }
        notify = TRUE;//通知回調函數
      }
      break;
  if ( notify == TRUE )
  {
      // Notify the application with the new state change
      if ( pGapRoles_AppCGs && pGapRoles_AppCGs->pfnStateChange ) //判斷是否設置了回調函數
      {
           pGapRoles_AppCGs->pfnStateChange( gapRole_state );//調用設置的回調函數，通知gapRole_state當前狀態
      }
  }

1. 廣播時產生一個GAP_LINK_ESTABLISHED_EVENT消息

static void gapRole_ProcessGAPMsg( gapEventHdr_t *pMsg )  //鏈路處理連接消息
{
  uint8 notify = FALSE;   // State changed notify the app? (default no)
  switch ( pMsg->opcode )
  {  
    case GAP_LINK_ESTABLISHED_EVENT:
      {
        gapEstLinkReqEvent_t *pPkt = (gapEstLinkReqEvent_t *)pMsg;
        if ( pPkt->hdr.status == SUCCESS )
        {
          VOID osal_memcpy( gapRole_ConnectedDevAddr, pPkt->devAddr, B_ADDR_LEN );//保存主機的地址
          gapRole_ConnectionHandle = pPkt->connectionHandle; //保存主機連接句柄
          gapRole_state = GAPROLE_CONNECTED;  //通知鏈路狀態：連接成功
              notify = TRUE;
        }
      }
 }