Ztack学习笔记(4)-系统网络分析

协调器的组网，终端设备和路由设备发现网络以及加入网络

//第一步：Z-Stack  由 main（）函数开始执行，main（）函数共做了 2 件事：一是系统初始化，另外一件是开始执行轮转查询式操作系统
 int main( void )
{
  .......
  // Initialize the operating system
  osal_init_system();              //第二步，操作系统初始化
......
  osal_start_system();   //初始化完系统任务事件后，正式开始执行操作系统
  ......
} 

//第二步，进入 osal_init_system()函数，执行操作系统初始化
uint8 osal_init_system( void )      //初始化操作系统，其中最重要的是，初始化操作系统的任务
{
  // Initialize the Memory Allocation System
  osal_mem_init();

  // Initialize the message queue
  osal_qHead = NULL;

  // Initialize the timers
  osalTimerInit();

  // Initialize the Power Management System
  osal_pwrmgr_init();

  // Initialize the system tasks.
  osalInitTasks();                 //第三步，执行操作系统任务初始化函数

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

//第三步，进入osalInitTasks()函数，执行操作系统任务初始化
void osalInitTasks( void )       //第三步，初始化操作系统任务
{
  uint8 taskID = ;
  tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);
  osal_memset( tasksEvents, , (sizeof( uint16 ) * tasksCnt));

  //任务优先级由高向低依次排列，高优先级对应 taskID 的值反而小
  macTaskInit( taskID++ ); //不需要用户考虑
  nwk_init( taskID++ );      //不需要用户考虑
  Hal_Init( taskID++ );      //硬件抽象层初始化，需要我们考虑
#if defined( MT_TASK )
  MT_TaskInit( taskID++ );
#endif
  APS_Init( taskID++ );       //不需要用户考虑
#if defined ( ZIGBEE_FRAGMENTATION )
  APSF_Init( taskID++ );
#endif
  ZDApp_Init( taskID++ );   //第四步，ZDApp层，初始化  ，执行ZDApp_init函数后，如果是协调器将建立网络，如果是终端设备将加入网络。
#if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
  ZDNwkMgr_Init( taskID++ );
#endif
  SerialApp_Init( taskID );  //应用层SerialApp层初始化，需要用户考虑     在此处设置了一个按键触发事件，
                                         //当有按键按下的时候，产生一个系统消息
}                            

//第四步，进入ZDApp_init()函数，执行ZDApp层初始化
//The first step
void ZDApp_Init( uint8 task_id )     //The first step,ZDApp层初始化。
{
  // Save the task ID
  ZDAppTaskID = task_id;

  // Initialize the ZDO global device short address storage
  ZDAppNwkAddr.addrMode = Addr16Bit;
  ZDAppNwkAddr.addr.shortAddr = INVALID_NODE_ADDR;
  (void)NLME_GetExtAddr();  // Load the saveExtAddr pointer.

  // Check for manual "Hold Auto Start"
  ZDAppCheckForHoldKey();

  // Initialize ZDO items and setup the device - type of device to create.
  ZDO_Init();

  // Register the endpoint description with the AF
  // This task doesn't have a Simple description, but we still need
  // to register the endpoint.
  afRegister( (endPointDesc_t *)&ZDApp_epDesc );

#if defined( ZDO_USERDESC_RESPONSE )
  ZDApp_InitUserDesc();
#endif // ZDO_USERDESC_RESPONSE

  // Start the device?
  if ( devState != DEV_HOLD )        //devState 初值为DEV_INIT ， 所以在初始化ZDA层时，就执行该条件语句
  {
    ZDOInitDevice(  );     //The second step, 接着转到ZDOInitDevice（）函数，执行The third step;
  }
  else
  {
    // Blink LED to indicate HOLD_START
    HalLedBlink ( HAL_LED_4, , ,  );
  }
  ZDApp_RegisterCBs();
} /* ZDApp_Init() */

//The third step,执行ZDOInitDevice()函数，执行设备初始化
uint8 ZDOInitDevice( uint16 startDelay )  //The third step， ZDO层初始化设备，
{
   .......
// Trigger the network start
  ZDApp_NetworkInit( extendedDelay );   //网络初始化，跳到相应的函数里头，执行The fourth step
   .......
}

//The fouth step,执行 ZDApp_NetWorkInit()函数
void ZDApp_NetworkInit( uint16 delay )  //The fourth step,网络初始化
{
  if ( delay )
  {
    // Wait awhile before starting the device
    osal_start_timerEx( ZDAppTaskID, ZDO_NETWORK_INIT, delay );    //发送ZDO_NETWORK_INIT（网络初始化）消息到 ZDApp层，转到                                                                                                                  //ZDApp层，执行The fifth step  ， ZDApp_event_loop() 函数
  }
  else
  {
    osal_set_event( ZDAppTaskID, ZDO_NETWORK_INIT );
  }
}

//The fifth step,转到ZDApp_event_loop()函数
UINT16 ZDApp_event_loop( uint8 task_id, UINT16 events )
{
if ( events & ZDO_NETWORK_INIT )   //The fivth step，网络初始化事件处理
  {
    // Initialize apps and start the network
    devState = DEV_INIT;

    //设备逻辑类型，启动模式，信标时间，超帧长度，接着转到The sixth step，去启动设备，接着执行The sixth step,转到ZDO_StartDevice()
    ZDO_StartDevice( (uint8)ZDO_Config_Node_Descriptor.LogicalType, devStartMode,
                     DEFAULT_BEACON_ORDER, DEFAULT_SUPERFRAME_ORDER );

    // Return unprocessed events
    return (events ^ ZDO_NETWORK_INIT);
  }
}

//The sixth step,执行ZDO_StartDevice()函数，启动设备
void ZDO_StartDevice( byte logicalType, devStartModes_t startMode, byte beaconOrder, byte superframeOrder ) //The sixth step
{
......
 if ( ZG_BUILD_COORDINATOR_TYPE && logicalType == NODETYPE_COORDINATOR )   //当设备作为协调器时，执行这个条件语句。
  {
    if ( startMode == MODE_HARD )
    {
      devState = DEV_COORD_STARTING;  

       //向网络层发送网络形成请求。当网络层执行 NLME_NetworkFormationRequest（）建立网络后，将给予 ZDO层反馈信息。
       // 接着转到The seventh step,去执行ZDApp层的  ZDO_NetworkFormationConfirmCB（）函数
      ret = NLME_NetworkFormationRequest( zgConfigPANID, zgApsUseExtendedPANID, zgDefaultChannelList,
                                          zgDefaultStartingScanDuration, beaconOrder,
                                          superframeOrder, false );
    }
if ( ZG_BUILD_JOINING_TYPE && (logicalType == NODETYPE_ROUTER || logicalType == NODETYPE_DEVICE) ) //当为终端设备或路由时
  {
    if ( (startMode == MODE_JOIN) || (startMode == MODE_REJOIN) )
    {
      devState = DEV_NWK_DISC;

      // zgDefaultChannelList与协调器形成网络的通道号匹配。 网络发现请求。
      // 继而转到ZDO_NetworkDiscoveryConfirmCB（）函数
      ret = NLME_NetworkDiscoveryRequest( zgDefaultChannelList, zgDefaultStartingScanDuration );
    }
  }
......
}

//The seventh step，分两种情况，1.协调器   2.路由器或终端设备
 ）协调器
void ZDO_NetworkFormationConfirmCB( ZStatus_t Status ) //The seventh step，给予ZDO层网络形成反馈信息（协调器）
{
osal_set_event( ZDAppTaskID, ZDO_NETWORK_START ); //发送网络启动事件 到 ZDApp层，接着转到ZDApp_event_loop（）函数
......
}

UINT16 ZDApp_event_loop( uint8 task_id, UINT16 events )
{
......
if ( events & ZDO_NETWORK_START )  // 网络启动事件
    {
      ZDApp_NetworkStartEvt();    //网络启动事件，接着跳转到The ninth step, 执行ZDApp_NetworkStartEvt()函数
  ......
    }
}

void ZDApp_NetworkStartEvt( void )     //处理网络启动事件
{
......
 osal_pwrmgr_device( PWRMGR_ALWAYS_ON );                           //电源总是上电
 osal_set_event( ZDAppTaskID, ZDO_STATE_CHANGE_EVT ); //设置网络状态改变事件，发送到ZDApp层，转到The tenth step,去
 ......                                                                                                 // ZDApp_event_loop（）函数，找到相对应的网络改变事件。
}

)路由器或终端设备
//The seventh step（终端设备）， 当发现有网络存在时，网络层将给予 ZDO 层发现网络反馈信息
ZStatus_t ZDO_NetworkDiscoveryConfirmCB( uint8 ResultCount, networkDesc_t *NetworkList )
{
   .......
  //把网络发现这个反馈消息，发送到ZDA层，转到 ZDApp_ProcessOSALMsg（），执行
  ZDApp_SendMsg( ZDAppTaskID, ZDO_NWK_DISC_CNF, sizeof(ZDO_NetworkDiscoveryCfm_t), (uint8 *)&msg );
}

void ZDApp_ProcessOSALMsg( osal_event_hdr_t *msgPtr )
{
   ......
   case ZDO_NWK_DISC_CNF:      // (终端设备），网络发现响应。
   ......
          //当发现有网络存在时，网络层将给予 ZDO 层发现网络反馈信息。然后由网络层发起加入网络请求，
          //如加入网络成功，则网络层将给予 ZDO 层加入网络反馈,执行NLME_JoinRequest()函数。然后转到
          //The ninth step,执行 ZDO_JoinConfirmCB()函数
            if ( NLME_JoinRequest( ((ZDO_NetworkDiscoveryCfm_t *)msgPtr)->extendedPANID,
                 BUILD_UINT16( ((ZDO_NetworkDiscoveryCfm_t *)msgPtr)->panIdLSB, ((ZDO_NetworkDiscoveryCfm_t *)msgPtr)->panIdMSB ),
                 ((ZDO_NetworkDiscoveryCfm_t *)msgPtr)->logicalChannel,
                 ZDO_Config_Node_Descriptor.CapabilityFlags ) != ZSuccess )
            {
              ZDApp_NetworkInit( (uint16)(NWK_START_DELAY
                  + ((uint16)(osal_rand()& EXTENDED_JOINING_RANDOM_MASK))) );
            }
          ......
   }

void ZDO_JoinConfirmCB( uint16 PanId, ZStatus_t Status )  //The ninth step（终端设备）, 终端设备加入网络响应。
{
......
//将ZDO_NWK_JOIN_IND事件发送到ZDA层，执行 ZDApp_ProcessOSALMsg（）函数。
  ZDApp_SendMsg( ZDAppTaskID, ZDO_NWK_JOIN_IND, sizeof(osal_event_hdr_t), (byte*)NULL );
}

void ZDApp_ProcessOSALMsg( osal_event_hdr_t *msgPtr )
{
......
 case ZDO_NWK_JOIN_IND:            //终端设备，加入网络反馈信息事件。
      if ( ZG_BUILD_JOINING_TYPE && ZG_DEVICE_JOINING_TYPE )
      {
        ZDApp_ProcessNetworkJoin(); //转到ZDApp_ProcessNetworkJoin()，执行ZDApp_ProcessNetworkJoin()函数。
      }
      break;
......
} 

在执行ZDApp_ProcessNetworkJoin()函数的时候，要分两种情况，一种是终端设备，一种是路由器：
)终端设备：
void ZDApp_ProcessNetworkJoin( void )  //处理网络加入事件。
{
......
if ( nwkStatus == ZSuccess )
    {
      //设置 ZDO_STATE_CHANGE_EVT ，发送到ZDA层，执行 ZDApp_event_loop（）函数。
      osal_set_event( ZDAppTaskID, ZDO_STATE_CHANGE_EVT );
    }
......
}

)路由器：
void ZDApp_ProcessNetworkJoin( void )
{
......
  if ( ZSTACK_ROUTER_BUILD )
        {
          // NOTE: first two parameters are not used, see NLMEDE.h for details
          if ( ZDO_Config_Node_Descriptor.LogicalType != NODETYPE_DEVICE )
          {
            NLME_StartRouterRequest( , , false );               //路由启动请求
          }
        }
......
}

void ZDO_StartRouterConfirmCB( ZStatus_t Status )
{
  nwkStatus = (byte)Status;
......
  osal_set_event( ZDAppTaskID, ZDO_ROUTER_START );
}

UINT16 ZDApp_event_loop( uint8 task_id, UINT16 events )
{
  if ( events & ZDO_ROUTER_START )
    {
      if ( nwkStatus == ZSuccess )
      {
        if ( devState == DEV_END_DEVICE )
          devState = DEV_ROUTER;                         //设备状态变成路由器

        osal_pwrmgr_device( PWRMGR_ALWAYS_ON );
      }
      else
      {
        // remain as end device!!
      }
      osal_set_event( ZDAppTaskID, ZDO_STATE_CHANGE_EVT );     //设置ZDO状态改变事件

      // Return unprocessed events
      return (events ^ ZDO_ROUTER_START);
    }
}

//The eighth step,执行ZDO状态改变事件
UINT16 ZDApp_event_loop( uint8 task_id, UINT16 events )
{
.......
if ( events & ZDO_STATE_CHANGE_EVT )  //The eighth step， 网络改变事件，这个事件就是在设备加入网络成功后，
                                                                     //并在网络中的身份确定后产生的一个事件
  {
    ZDO_UpdateNwkStatus( devState );  //更新网络状态，转到The eleventh step,执行 ZDO_UpdateNwkStatus（）函数。
  ......
  }
}

//The ninth step,执行ZDO_UpdateNwkStatus()函数，完成网络状态更新
void ZDO_UpdateNwkStatus(devStates_t state)  //The ninth step, 更新网络状态
{
......
      zdoSendStateChangeMsg(state, *(pItem->epDesc->task_id));  //发送状态改变消息到zdo层，这是The tenth step,转到
                                                                                                        //zdoSendStateChangeMsg（）函数
.......
  ZDAppNwkAddr.addr.shortAddr = NLME_GetShortAddr();  //调用NLME_GetShortAddr()函数，获得16位短地址。
  (void)NLME_GetExtAddr();  // Load the saveExtAddr pointer.  //获得64位的IEEE地址。

}

//The tenth step,执行zdoSendStateChangeMsg（）函数
static void zdoSendStateChangeMsg(uint8 state, uint8 taskId) //The tenth step,
{
  osal_event_hdr_t *pMsg = (osal_event_hdr_t *)osal_msg_find(taskId, ZDO_STATE_CHANGE);

  if (NULL == pMsg)
  {
    if (NULL == (pMsg = (osal_event_hdr_t *)osal_msg_allocate(sizeof(osal_event_hdr_t))))
    {
      // Upon failure to notify any EndPoint of the state change, re-set the ZDO event to
      // try again later when more Heap may be available.
      osal_set_event(ZDAppTaskID, ZDO_STATE_CHANGE_EVT);  //如果ZDO状态没有任何改变，再一次，跳到
                                                                                                        //ZDO_STATE_CHANGE_EVT事件处理函数。
    }
    else
    {
      pMsg->event = ZDO_STATE_CHANGE;      //如果ZDO状态改变了 了，把ZDO_STATE_CHANGE这个消息保存到pMsg
      pMsg->status = state;

      (void)osal_msg_send(taskId, (uint8 *)pMsg);    //转到MT_TASK.C，去执行The eleven step, MT_ProcessIncomingCommand()函数
    }
  }
  ......
}
//The eleventh step,去执行MT_ProcessIncomingCommand()函数
void MT_ProcessIncomingCommand( mtOSALSerialData_t *msg )
{
......
case ZDO_STATE_CHANGE:        //The thirteenth step, 接着跳到MT_ZdoStateChangeCB（）函数。
                                                      //自此，协调器组网形成（终端设备成功加入网络）
         MT_ZdoStateChangeCB((osal_event_hdr_t *)msg);
         break;
......
}

//第五步，//初始化玩系统任务事件后，正是开始执行操作系统，此时操作系统不断的检测有没有任务事件发生，一旦检测到有事件发生，就转 //到相应的处理函数，进行处理。
void osal_start_system( void )  //第五步，正式执行操作系统
{
#if !defined ( ZBIT ) && !defined ( UBIT )
  for(;;)  // Forever Loop     //死循环
#endif
  {
    uint8 idx = ;
    osalTimeUpdate();
    Hal_ProcessPoll();  // This replaces MT_SerialPoll() and osal_check_timer().
    do {
      if (tasksEvents[idx])  // Task is highest priority that is ready.
      {
        break;        // 得到待处理的最高优先级任务索引号idx
      }
    } while (++idx < tasksCnt);

    if (idx < tasksCnt)
    {
      uint16 events;
      halIntState_t intState;
      HAL_ENTER_CRITICAL_SECTION(intState);  //进入临界区
      events = tasksEvents[idx];             //提取需要处理的任务中的事件
      tasksEvents[idx] = ;  // Clear the Events for this task.   // 清除本次任务的事件
      HAL_EXIT_CRITICAL_SECTION(intState);   //退出临界区

      events = (tasksArr[idx])( idx, events ); //通过指针调用任务处理函数  ， 紧接着跳到相应的函数去处理，此为第五步

      HAL_ENTER_CRITICAL_SECTION(intState);  //进入临界区
      tasksEvents[idx] |= events;  // Add back unprocessed events to the current task.  // 保存未处理的事件
      HAL_EXIT_CRITICAL_SECTION(intState);   //退出临界区
    }
#if defined( POWER_SAVING )
    else  // Complete pass through all task events with no activity?
    {
      osal_pwrmgr_powerconserve();  // Put the processor/system into sleep
    }
#endif
  }
}

//ZDApp.c
 1 void ZDApp_Init( uint8 task_id )
 {
   // Save the task ID
   ZDAppTaskID = task_id;

   // Initialize the ZDO global device short address storage
   ZDAppNwkAddr.addrMode = Addr16Bit;
   ZDAppNwkAddr.addr.shortAddr = INVALID_NODE_ADDR;//0xFFFE
   (void)NLME_GetExtAddr();  // Load the saveExtAddr pointer.

   // Check for manual "Hold Auto Start"
   ZDAppCheckForHoldKey();检测到有手工置位SW_1则会设置devState = DEV_HOLD,从而避开网络初始化

   // Initialize ZDO items and setup the device - type of device to create.
   ZDO_Init();//通过判断预编译来开启一些函数功能

   // Register the endpoint description with the AF
   // This task doesn't have a Simple description, but we still need
   // to register the endpoint.
   afRegister( (endPointDesc_t *)&ZDApp_epDesc );

 #if defined( ZDO_USERDESC_RESPONSE )
   ZDApp_InitUserDesc();
 #endif // ZDO_USERDESC_RESPONSE

   // Start the device?
   if ( devState != DEV_HOLD ) //devState 初值为DEV_INIT ， 所以在初始化ZDA层时，就执行该条件语句
   /*如果devState=DEV_HOLD,则不会调用ZDOInitDevice()来初始化网络
    即不组网也不入网.LED4闪烁等待应用程序来开启设备并初始化网络
  */
   {
     ZDOInitDevice(  );
   }
   else
   {
     ZDOInitDevice( ZDO_INIT_HOLD_NWK_START );
     // Blink LED to indicate HOLD_START
     HalLedBlink ( HAL_LED_4, , ,  );
   }

   // Initialize the ZDO callback function pointers zdoCBFunc[]
   ZDApp_InitZdoCBFunc();

   ZDApp_RegisterCBs();
 } /* ZDApp_Init() */

 //ZDApp.c
 1 uint8 ZDOInitDevice( uint16 startDelay )
 {
   uint8 networkStateNV = ZDO_INITDEV_NEW_NETWORK_STATE;
   uint16 extendedDelay = ;

   if ( devState == DEV_HOLD )
   {
     // Initialize the RAM items table, in case an NV item has been updated.
     zgInitItems( FALSE );
   }

   ZDConfig_InitDescriptors();
   //devtag.071807.todo - fix this temporary solution
   _NIB.CapabilityFlags = ZDO_Config_Node_Descriptor.CapabilityFlags;

 #if defined ( NV_RESTORE )
   // Get Keypad directly to see if a reset nv is needed.
   // Hold down the SW_BYPASS_NV key (defined in OnBoard.h)
   // while booting to skip past NV Restore.
   if ( HalKeyRead() == SW_BYPASS_NV )
     networkStateNV = ZDO_INITDEV_NEW_NETWORK_STATE;
   else
   {
     // Determine if NV should be restored
     networkStateNV = ZDApp_ReadNetworkRestoreState();
   }

   if ( networkStateNV == ZDO_INITDEV_RESTORED_NETWORK_STATE )
   {
     networkStateNV = ZDApp_RestoreNetworkState();
   }
   else
   {
     // Wipe out the network state in NV
     NLME_InitNV();
     NLME_SetDefaultNV();
     // clear NWK key values
     ZDSecMgrClearNVKeyValues();
   }
 #endif

   if ( networkStateNV == ZDO_INITDEV_NEW_NETWORK_STATE )
   {
     ZDAppDetermineDeviceType();

     // Only delay if joining network - not restoring network state
     extendedDelay = (uint16)((NWK_START_DELAY + startDelay)
               + (osal_rand() & EXTENDED_JOINING_RANDOM_MASK));
   }

   // Initialize the security for type of device
   ZDApp_SecInit( networkStateNV );

   if( ZDO_INIT_HOLD_NWK_START != startDelay )
   {
     devState = DEV_INIT;    // Remove the Hold state

     // Initialize leave control logic
     ZDApp_LeaveCtrlInit();

     // Check leave control reset settings
     ZDApp_LeaveCtrlStartup( &devState, &startDelay );

     // Leave may make the hold state come back
     if ( devState == DEV_HOLD )
     {
       // Set the NV startup option to force a "new" join.
       zgWriteStartupOptions( ZG_STARTUP_SET, ZCD_STARTOPT_DEFAULT_NETWORK_STATE );

       // Notify the applications
       osal_set_event( ZDAppTaskID, ZDO_STATE_CHANGE_EVT );

       return ( ZDO_INITDEV_LEAVE_NOT_STARTED );   // Don't join - (one time).
     }

     // Trigger the network start
     ZDApp_NetworkInit( extendedDelay ); //网络初始化，跳到相应的函数里头
   }

   // set broadcast address mask to support broadcast filtering
   NLME_SetBroadcastFilter( ZDO_Config_Node_Descriptor.CapabilityFlags );

   return ( networkStateNV );
 }

 void ZDApp_NetworkInit( uint16 delay )
 {
   if ( delay )
   {
     // Wait awhile before starting the device
     osal_start_timerEx( ZDAppTaskID, ZDO_NETWORK_INIT, delay );
     //发送ZDO_NETWORK_INIT（网络初始化）消息到 ZDApp层，转到                                                                                                                  //ZDApp层，执行The fifth step  ， ZDApp_event_loop() 函数
   }
   else
   {
     osal_set_event( ZDAppTaskID, ZDO_NETWORK_INIT );
   }
 }

 UINT16 ZDApp_event_loop( uint8 task_id, UINT16 events )
 {
   uint8 *msg_ptr;

   if ( events & SYS_EVENT_MSG )
   {
     while ( (msg_ptr = osal_msg_receive( ZDAppTaskID )) )
     {
       ZDApp_ProcessOSALMsg( (osal_event_hdr_t *)msg_ptr );

       // Release the memory
       osal_msg_deallocate( msg_ptr );
     }

     // Return unprocessed events
     return (events ^ SYS_EVENT_MSG);
   }

   if ( events & ZDO_NETWORK_INIT )//网络初始化事件处理
   {
     // Initialize apps and start the network
     devState = DEV_INIT;
     osal_set_event( ZDAppTaskID, ZDO_STATE_CHANGE_EVT );

     ZDO_StartDevice( (uint8)ZDO_Config_Node_Descriptor.LogicalType, devStartMode,
                      DEFAULT_BEACON_ORDER, DEFAULT_SUPERFRAME_ORDER );
 //设备逻辑类型，启动模式，信标时间，超帧长度，去启动设备
     // Return unprocessed events
     return (events ^ ZDO_NETWORK_INIT);
   }

   if ( ZSTACK_ROUTER_BUILD )
   {
     if ( events & ZDO_NETWORK_START )
     {
       ZDApp_NetworkStartEvt();

       // Return unprocessed events
       return (events ^ ZDO_NETWORK_START);
     }

     if ( events & ZDO_ROUTER_START )
     {
       if ( nwkStatus == ZSuccess )
       {
         if ( devState == DEV_END_DEVICE )
           devState = DEV_ROUTER;

         osal_pwrmgr_device( PWRMGR_ALWAYS_ON );
       }
       else
       {
         // remain as end device!!
       }
       osal_set_event( ZDAppTaskID, ZDO_STATE_CHANGE_EVT );

       // Return unprocessed events
       return (events ^ ZDO_ROUTER_START);
     }
   }

   if ( events & ZDO_STATE_CHANGE_EVT )
   {
     ZDO_UpdateNwkStatus( devState );

     // At start up, do one MTO route discovery if the device is a concentrator
     if ( zgConcentratorEnable == TRUE )
     {
       // Start next event
       osal_start_timerEx( NWK_TaskID, NWK_MTO_RTG_REQ_EVT,  );
     }

     // Return unprocessed events
     return (events ^ ZDO_STATE_CHANGE_EVT);
   }

   if ( events & ZDO_COMMAND_CNF )
   {
     // User defined logic

     // Return unprocessed events
     return (events ^ ZDO_COMMAND_CNF);
   }

   if ( events & ZDO_NWK_UPDATE_NV )
   {
     ZDApp_SaveNetworkStateEvt();

     // Return unprocessed events
     return (events ^ ZDO_NWK_UPDATE_NV);
   }

   if ( events & ZDO_DEVICE_RESET )
   {
 #ifdef ZBA_FALLBACK_NWKKEY
     if ( devState == DEV_END_DEVICE_UNAUTH )
     {
       ZDSecMgrFallbackNwkKey();
     }
     else
 #endif
     {
       // Set the NV startup option to force a "new" join.
       zgWriteStartupOptions( ZG_STARTUP_SET, ZCD_STARTOPT_DEFAULT_NETWORK_STATE );

       // The device has been in the UNAUTH state, so reset
       // Note: there will be no return from this call
       SystemResetSoft();
     }
   }

   if ( ZG_SECURE_ENABLED )
   {
     return ( ZDApp_ProcessSecEvent( task_id, events ) );
   }
   else
   {
     // Discard or make more handlers
     return ;
   }
 }

  //ZDObject.c
  1 void ZDO_StartDevice( byte logicalType, devStartModes_t startMode, byte beaconOrder, byte superframeOrder )
 {
   ZStatus_t ret;
 #if defined ( ZIGBEE_FREQ_AGILITY )
   static uint8 discRetries = ;
 #endif
 #if defined ( ZIGBEE_COMMISSIONING )
   static uint8 scanCnt = ;
 #endif

   ret = ZUnsupportedMode;

   if ( ZG_BUILD_COORDINATOR_TYPE && logicalType == NODETYPE_COORDINATOR )//当设备作为协调器时，执行这个条件语句。
   {
     if ( startMode == MODE_HARD )
     {
       devState = DEV_COORD_STARTING;
       ret = NLME_NetworkFormationRequest( zgConfigPANID, zgApsUseExtendedPANID, zgDefaultChannelList,
                                           zgDefaultStartingScanDuration, beaconOrder,
                                           superframeOrder, false );

//向网络层发送网络形成请求。当网络层执行 NLME_NetworkFormationRequest（）建立网络后，将给予 ZDO层反馈信息。

// 接着去执行ZDApp层的 ZDO_NetworkFormationConfirmCB（）函数

     }
     else if ( startMode == MODE_RESUME )
     {
       // Just start the coordinator
       devState = DEV_COORD_STARTING;
       ret = NLME_StartRouterRequest( beaconOrder, beaconOrder, false );
     }
     else
     {
 #if defined( LCD_SUPPORTED )
       HalLcdWriteScreen( "StartDevice ERR", "MODE unknown" );
 #endif
     }
   }

   if ( ZG_BUILD_JOINING_TYPE && (logicalType == NODETYPE_ROUTER || logicalType == NODETYPE_DEVICE) )//当为终端设备或路由时
   {
     if ( (startMode == MODE_JOIN) || (startMode == MODE_REJOIN) )
     {
       devState = DEV_NWK_DISC;

//zgDefaultChannelList与协调器形成网络的通道号匹配。 网络发现请求。

// 继而转到ZDO_NetworkDiscoveryConfirmCB（）函数

   #if defined( MANAGED_SCAN )
       ZDOManagedScan_Next();
       ret = NLME_NetworkDiscoveryRequest( managedScanChannelMask, BEACON_ORDER_15_MSEC );
   #else
       ret = NLME_NetworkDiscoveryRequest( zgDefaultChannelList, zgDefaultStartingScanDuration );
     #if defined ( ZIGBEE_FREQ_AGILITY )
       if ( !( ZDO_Config_Node_Descriptor.CapabilityFlags & CAPINFO_RCVR_ON_IDLE ) &&
             ( ret == ZSuccess ) && ( ++discRetries ==  ) )
       {
         // For devices with RxOnWhenIdle equals to FALSE, any network channel
         // change will not be recieved. On these devices or routers that have
         // lost the network, an active scan shall be conducted on the Default
         // Channel list using the extended PANID to find the network. If the
         // extended PANID isn't found using the Default Channel list, an scan
         // should be completed using all channels.
         zgDefaultChannelList = MAX_CHANNELS_24GHZ;
       }
     #endif // ZIGBEE_FREQ_AGILITY
     #if defined ( ZIGBEE_COMMISSIONING )
       if (startMode == MODE_REJOIN && scanCnt++ >=  )
       {
         // When ApsUseExtendedPanID is commissioned to a non zero value via
         // application specific means, the device shall conduct an active scan
         // on the Default Channel list and join the PAN with the same
         // ExtendedPanID. If the PAN is not found, an scan should be completed
         // on all channels.
         // When devices rejoin the network and the PAN is not found from
         zgDefaultChannelList = MAX_CHANNELS_24GHZ;
       }
     #endif // ZIGBEE_COMMISSIONING
   #endif
     }
     else if ( startMode == MODE_RESUME )
     {
       if ( logicalType == NODETYPE_ROUTER )
       {
         ZMacScanCnf_t scanCnf;
         devState = DEV_NWK_ORPHAN;

         /* if router and nvram is available, fake successful orphan scan */
         scanCnf.hdr.Status = ZSUCCESS;
         scanCnf.ScanType = ZMAC_ORPHAN_SCAN;
         scanCnf.UnscannedChannels = ;
         scanCnf.ResultListSize = ;
         nwk_ScanJoiningOrphan(&scanCnf);

         ret = ZSuccess;
       }
       else
       {
         devState = DEV_NWK_ORPHAN;
         ret = NLME_OrphanJoinRequest( zgDefaultChannelList,
                                       zgDefaultStartingScanDuration );
       }
     }
     else
     {
 #if defined( LCD_SUPPORTED )
       HalLcdWriteScreen( "StartDevice ERR", "MODE unknown" );
 #endif
     }
   }

   if ( ret != ZSuccess )
   {
     osal_start_timerEx(ZDAppTaskID, ZDO_NETWORK_INIT, NWK_RETRY_DELAY );
   }
 }

void ZDO_NetworkFormationConfirmCB( ZStatus_t Status )

网络的格式化
          A：初始化的能量阀值为16。通过设置ZDApp_event_loop任务中的事件ID为ZDO_NETWORK_INIT以便执行B。
          B：调用NLME_NetworkFormationRequest函数进行申请，对申请的回应在程序中没对应的回调处理，猜想回调处理在lib库中处理。在程序找到了两个对申请结果作处理的函数，void ZDO_NetworkFormationConfirmCB( ZStatus_t Status )和void nwk_Status( uint16 statusCode,uint16 statusValue )；在两个函数中都有申请的结果。如果不成功则nwk_Status先执行如果成功则ZDO_NetworkFormationConfirmCB先执行。
          C：系统（lib）调用ZDO_NetworkFormationConfirmCB函数，在函数中通过设置ZDApp_event_loop任务中的事件ID为ZDO_NETWORK_START以便执行D。
          D：调用ZDApp_NetworkStartEvt函数，在函数中检测返回的申请结果，如果不成功则能量阀值增加16并将ZDApp_event_loop任务中的事件ID置为ZDO_NETWORK_INIT以便执行B；如果成功则ZDApp_event_loop任务中的事件ID置为ZDO_STATE_CHANGE_EVT以便执行E。
          E：调用ZDO_UpdateNwkStatus函数，函数通过端点表向SampleApp_ProcessEvent任务发送一个ZDO_STATE_CHANGE命令，以便执行F。
          F：设置ZDApp_event_loop任务中的事件ID为SAMPLEAPP_SEND_PERIODIC_MSG_EVT以便执行G。
          G：发送一个定期信息，并设置ZDApp_event_loop任务中的事件ID为SAMPLEAPP_SEND_PERIODIC_MSG_EVT以便执行G。

参考链接

【1】Zigbee协议栈学习之串口透明传输实验（SerialApp）流程分析

【2】协调器网络的建立