Ztack学习笔记(2)-系统初始化分析

main函数先执行初始化工作，包括硬件、网络层、任务等的初始化。

一 系统初始化

系统初始化函数主要完成内存分配、消息队列头、定时器、电源管理、任务系统及内存栈等的初始化，具体如下代码所示：

 //osal.c
 1 uint8 osal_init_system( void )
 {
   // Initialize the Memory Allocation System
   osal_mem_init();/*初始化内存分配系统*/

   // Initialize the message queue
   osal_qHead = NULL;  /*初始化系统消息队列*/

   // Initialize the timers
   osalTimerInit(); /*初始化定时器*/

   // Initialize the Power Management System
   osal_pwrmgr_init(); /*初始化电源管理系统*/

   // Initialize the system tasks.
   osalInitTasks();/*初始化系统任务*/

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

   return ( SUCCESS );
 }

 二 任务初始化

任务初始化，就是为系统的各个任务分配存储空间,初始化后，内存空间为全0(NULL),然后为各任务分配任务标识号taskID。即，这里重点是各任务的初始化，MAC层和NWK层的未开源看不到。

 //OSAL_SampleApp.c
 1 void osalInitTasks( void )
 {
   uint8 taskID = ;

   tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);//为当前OSAL中的各任务分配存储空间(实际上是一个任务数组),函数返回指向任务缓冲区的指针，因此tasksEvents指向该任务数组的首地址。
   osal_memset( tasksEvents, , (sizeof( uint16 ) * tasksCnt));
 //把开辟的内存全部设置为0；sizeof( uint16 )是4个字节，即一个任务的长度（同样是uint16定义），乘以任务数量tasksCnt，即全部内存空间
   macTaskInit( taskID++ );//初始化各层任务 mac_taskID=0;
   nwk_init( taskID++ );
   Hal_Init( taskID++ );
 #if defined( MT_TASK )
   MT_TaskInit( taskID++ );
 #endif
   APS_Init( taskID++ );
 #if defined ( ZIGBEE_FRAGMENTATION )
   APSF_Init( taskID++ );
 #endif
   ZDApp_Init( taskID++ );
 #if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
   ZDNwkMgr_Init( taskID++ );
 #endif
   SampleApp_Init( taskID );//SampleApp_taskID=6;用户创建的任务
 }

系统主循环函数里tasksEvents[ idx]和tasksArr[ idx]的idx与这里taskID是一一对应关系。数组tasksEvents[]里面元素是各任务事件，不是指向任务事件的指针，数组tasksArr[ ]是这个指针数组，里面元素是指向各任务事件处理函数的指针，这两个指针数组里面各元素的顺序要一一对应,因为后面需要相应任务调用相应事件处理函数。如下代码所示，其中的xx_loop与上面的yy_init是一一对应的关系。

//OSAL_Tasks.h
typedef unsigned short (*pTaskEventHandlerFn)( unsigned char task_id, unsigned short event );
//OSAL_SampleApp.c
const pTaskEventHandlerFn tasksArr[] = {
  macEventLoop,
  nwk_event_loop,
  Hal_ProcessEvent,
#if defined( MT_TASK )
  MT_ProcessEvent,
#endif
  APS_event_loop,
#if defined ( ZIGBEE_FRAGMENTATION )
  APSF_ProcessEvent,
#endif
  ZDApp_event_loop,
#if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
  ZDNwkMgr_event_loop,
#endif
  SampleApp_ProcessEvent
};

const uint8 tasksCnt = sizeof( tasksArr ) / sizeof( tasksArr[] );

三 应用初始化

 void SampleApp_Init( uint8 task_id )
 {
   SampleApp_TaskID = task_id;//osal分配的任务ID，这里为6，随着用户添加任务的增多而改变
   SampleApp_NwkState = DEV_INIT;//设备状态设定为ZDO层中定义的初始化状态（无连接）
   SampleApp_TransID = ;//消息发送ID（多消息时有顺序之分）

   // Device hardware initialization can be added here or in main() (Zmain.c).
   // If the hardware is application specific - add it here.
   // If the hardware is other parts of the device add it in main().
 //以下是通过跳线判断是路由器还是协调器
  #if defined ( BUILD_ALL_DEVICES )
   // The "Demo" target is setup to have BUILD_ALL_DEVICES and HOLD_AUTO_START
   // We are looking at a jumper (defined in SampleAppHw.c) to be jumpered
   // together - if they are - we will start up a coordinator. Otherwise,
   // the device will start as a router.
   if ( readCoordinatorJumper() )
     zgDeviceLogicalType = ZG_DEVICETYPE_COORDINATOR;
   else
     zgDeviceLogicalType = ZG_DEVICETYPE_ROUTER;
 #endif // BUILD_ALL_DEVICES
 //以下是决断是通过外部按键触发还是系统启动过程中触发启动芯片
 #if defined ( HOLD_AUTO_START )
   // HOLD_AUTO_START is a compile option that will surpress ZDApp
   //  from starting the device and wait for the application to
   //  start the device.
   ZDOInitDevice();
 #endif
 //以下代码设置网络的通讯方式
   // Setup for the periodic message's destination address
   // Broadcast to everyone
   SampleApp_Periodic_DstAddr.addrMode = (afAddrMode_t)AddrBroadcast;
   SampleApp_Periodic_DstAddr.endPoint = SAMPLEAPP_ENDPOINT;
   SampleApp_Periodic_DstAddr.addr.shortAddr = 0xFFFF;

   // Setup for the flash command's destination address - Group 1
   SampleApp_Flash_DstAddr.addrMode = (afAddrMode_t)afAddrGroup;
   SampleApp_Flash_DstAddr.endPoint = SAMPLEAPP_ENDPOINT;
   SampleApp_Flash_DstAddr.addr.shortAddr = SAMPLEAPP_FLASH_GROUP;

   // Fill out the endpoint description.
   SampleApp_epDesc.endPoint = SAMPLEAPP_ENDPOINT;
   SampleApp_epDesc.task_id = &SampleApp_TaskID;
   SampleApp_epDesc.simpleDesc
             = (SimpleDescriptionFormat_t *)&SampleApp_SimpleDesc;
   SampleApp_epDesc.latencyReq = noLatencyReqs;

   // Register the endpoint description with the AF
   afRegister( &SampleApp_epDesc );

   // Register for all key events - This app will handle all key events
   RegisterForKeys( SampleApp_TaskID );

   // By default, all devices start out in Group 1
   SampleApp_Group.ID = 0x0001;
   osal_memcpy( SampleApp_Group.name, "Group 1",   );
   aps_AddGroup( SAMPLEAPP_ENDPOINT, &SampleApp_Group );

 #if defined ( LCD_SUPPORTED )
   HalLcdWriteString( "SampleApp", HAL_LCD_LINE_1 );
 #endif
 }

以上为OSAL初始化大体流程，OSAL以及各软硬部件初始化完成后,就进入了系统主循环函数osal_start_system()，下节将介绍此。

四 参考链接

【1】zstack sampleApp程序分析2