Zstack是Zigbee协议的代码实现，本次总结我在学习TI在51内核上开发的Zstack，由于zigbee栈实现起来非常复杂而困难，因此在本Zstack中引入了操作系统-OSAL，用来协调、调度各个任务，本篇将总结SampleApp在OSAL中的初始化及任务轮训的实现机制。当系统上电后，开始执行Zmian中的main函数，如下：
int main( void )
{
// Turn off interrupts
osal_int_disable( INTS_ALL ); //关闭所有中断
// Initialization for board related stuff such as LEDs
HAL_BOARD_INIT(); //初始化系统时钟
// Make sure supply voltage is high enough to run
zmain_vdd_check(); //检查芯片电压是否正常
// Initialize board I/O
InitBoard( OB_COLD ); //初始化I/O ，LED 、Timer 等
// Initialze HAL drivers
HalDriverInit(); //初始化芯片各硬件模块
// Initialize NV System
osal_nv_init( NULL ); //初始化Flash 存储器
// Initialize the MAC
ZMacInit(); //初始化MAC 层
// Determine the extended address
zmain_ext_addr(); //确定IEEE 64位地址
// Initialize basic NV items
zgInit(); //初始化非易失变量
#ifndef NONWK
// Since the AF isn't a task, call it's initialization routine
afInit();
#endif
// Initialize the operating system
<span style="color: rgb(255, 0, 0);">osal_init_system(); //初始化操作系统</span>
// Allow interrupts
osal_int_enable( INTS_ALL ); //使能全部中断
// Final board initialization
InitBoard( OB_READY ); //最终板载初始化
// Display information about this device
zmain_dev_info(); //显示设备信息
/* Display the device info on the LCD */
#ifdef LCD_SUPPORTED
zmain_lcd_init(); //初始化LCD
#endif
osalInitTasks();
#ifdef WDT_IN_PM1
/* If WDT is used, this is a good place to enable it. */
WatchDogEnable( WDTIMX );
#endif
<span style="color:#ff0000;">osal_start_system(); // No Return from here 执行操作系统，进去后不会返回</span>
return 0; // Shouldn't get here.
} // main()
其中红色标注osal_init_system()及osal_start_system()需要特别注意，其中osal_start_system()为启动操作系统（后面有介绍），而osal_init_system()为操作系统的初始化操作，其源代码如下：
uint8 osal_init_system( void )
{
// 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.
<span style="color:#ff0000;"> osalInitTasks(); </span>
// Setup efficient search for the first free block of heap.
osal_mem_kick();
return ( SUCCESS );
}
如上，操作系统的初始化包含了内存、消息队列、电源管理、任务队列等，其中我们需要特别关注红色标注的osalInitTasks()，此函数负责初始化系统任务，我们所写SampleApp任务在此函数内被初始化，源码如下：
void osalInitTasks( void )
{
uint8 taskID = 0;
// 分配内存，返回指向缓冲区的指针
tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);
// 设置所分配的内存空间单元值为0
osal_memset( tasksEvents, 0, (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++ ); //macTaskInit(0) ，用户不需考虑
nwk_init( taskID++ ); //nwk_init(1)，用户不需考虑
Hal_Init( taskID++ ); //Hal_Init(2) ，用户需考虑
#if defined( MT_TASK )
MT_TaskInit( taskID++ );
#endif
APS_Init( taskID++ ); //APS_Init(3) ，用户不需考虑
#if defined ( ZIGBEE_FRAGMENTATION )
APSF_Init( taskID++ );
#endif
ZDApp_Init( taskID++ ); //ZDApp_Init(4) ，用户需考虑
#if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
ZDNwkMgr_Init( taskID++ );
#endif
//用户创建的任务
<span style="color:#ff0000;">SampleApp_Init( taskID ); </span> // SampleApp_Init _Init(5) ，用户需考虑
}
红色标注部分是我们必须要写的，其中taskID为任务编号，升序排列，越大优先级越低，当初始化完任务后，操作系统启动后会不停查询任务事件，并根据taskID进行基于优先级的区别处理，在本次应用中其代码如下：
void SampleApp_Init( uint8 task_id )
{
SampleApp_TaskID = task_id; //osal分配的任务ID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
SampleApp_TransID = 0; //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().
#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
//该段的意思是，如果设置了HOLD_AUTO_START宏定义，将会在启动芯片的时候会暂停启动
//流程，只有外部触发以后才会启动芯片。其实就是需要一个按钮触发它的启动流程。
#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(0);
#endif
// Setup for the periodic message's destination address 设置发送数据的方式和目的地址寻址模式
// Broadcast to everyone 发送模式:广播发送
SampleApp_Periodic_DstAddr.addrMode = (afAddrMode_t)AddrBroadcast;//广播
SampleApp_Periodic_DstAddr.endPoint = SAMPLEAPP_ENDPOINT; //指定端点号:20
SampleApp_Periodic_DstAddr.addr.shortAddr = 0xFFFF;//指定目的网络地址为广播地址
// Setup for the flash command's destination address - Group 1 组播发送
SampleApp_Flash_DstAddr.addrMode = (afAddrMode_t)afAddrGroup; //组寻址
SampleApp_Flash_DstAddr.endPoint = SAMPLEAPP_ENDPOINT; //指定端点号:20,1~240
SampleApp_Flash_DstAddr.addr.shortAddr = SAMPLEAPP_FLASH_GROUP;//组号0x0001
// Fill out the endpoint description. 定义本设备用来通信的APS层端点描述符
SampleApp_epDesc.endPoint = SAMPLEAPP_ENDPOINT; //指定端点号:20
SampleApp_epDesc.task_id = &SampleApp_TaskID; //SampleApp 描述符的任务ID
SampleApp_epDesc.simpleDesc
= (SimpleDescriptionFormat_t *)&SampleApp_SimpleDesc;//SampleApp简单描述符
SampleApp_epDesc.latencyReq = noLatencyReqs; //延时策略
<span style="color:#ff0000;"> // Register the endpoint description with the AF
afRegister( &SampleApp_epDesc ); //向AF层登记描述符
// Register for all key events - This app will handle all key events
RegisterForKeys( SampleApp_TaskID ); // 登记所有的按键事件</span>
// By default, all devices start out in Group 1
SampleApp_Group.ID = 0x0001;//组号
osal_memcpy( SampleApp_Group.name, "Group 1", 7 );//设定组名
aps_AddGroup( SAMPLEAPP_ENDPOINT, &SampleApp_Group );//把该组登记添加到APS中
#if defined ( LCD_SUPPORTED )
HalLcdWriteString( "SampleApp", HAL_LCD_LINE_1 ); //如果支持LCD，显示提示信息
#endif
}
如上，红色标注部分依然是我们需要特别注意的，afRegister( &SampleApp_epDesc )该函数将endpoint注册至AF（即Aapplication Frame）层，该层负责管理端点进行数据传输；而RegisterForKeys( SampleApp_TaskID )是将所有的按键事件注册绑定到我们SampleApp中，注册后当有按键事件发生时，可以在系统的任务轮询中进入SampleApp的时间相应函数中，在本应用中该函数为SampleApp_ProcessEvent( uint8 task_id, uint16 events )；
操作系统的启动由osal_start_system()函数负责，该函数为整个上电启动过程最后的操作，进入该函数后会不停查询处理任务事件，该函数原型如下：
void osal_start_system( void )
{
#if !defined ( ZBIT ) && !defined ( UBIT )
for(;;) // Forever Loop
#endif
{
uint8 idx = 0;
osalTimeUpdate(); //扫描哪个事件被触发了，然后置相应的标志位
Hal_ProcessPoll(); //轮询TIMER与UART 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,保护
events = tasksEvents[idx]; //提取需要处理的任务中的事件
tasksEvents[idx] = 0; //清除本次任务的事件
HAL_EXIT_CRITICAL_SECTION(intState); // 退出临界区
<span style="color:#ff0000;"> events = (tasksArr[idx])( idx, events )</span>;//通过指针调用任务处理函数，关键，其中sampleAPP的处理函数即从此处调用
HAL_ENTER_CRITICAL_SECTION(intState); //进入临界区
tasksEvents[idx] |= events; // 保存未处理的事件 Add back unprocessed events to the current task.
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
}
}
如上，该函数为不断轮训任务时间，并根据任务ID进行处理（红色标注部分），跟踪tasksArr[idx]发现其被赋值如下：
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
<span style="color:#ff0000;">SampleApp_ProcessEvent</span>
};
其中 SampleApp_ProcessEvent为我们自定义应用事件处理函数，函数名可自定义，在本次应用中该函数的原型如下：
uint16 SampleApp_ProcessEvent( uint8 task_id, uint16 events )
{
afIncomingMSGPacket_t *MSGpkt;
(void)task_id; // Intentionally unreferenced parameter
if ( events & SYS_EVENT_MSG ) //接收系统消息再进行判断
{
//接收属于本应用任务SampleApp的消息，以SampleApp_TaskID标记
MSGpkt = (afIncomingMSGPacket_t *)osal_msg_receive( SampleApp_TaskID );
while ( MSGpkt )
{
switch ( MSGpkt->hdr.event )
{
// Received when a key is pressed
case <span style="color:#ff0000;">KEY_CHANGE</span>://按键事件
HalLedBlink(HAL_LED_2, 0, 50, 200);//如果是则Led1间隔200ms闪烁
SampleApp_HandleKeys( ((keyChange_t *)MSGpkt)->state, ((keyChange_t *)MSGpkt)->keys );
break;
// Received when a messages is received (OTA) for this endpoint
case <span style="color:#ff0000;">AF_INCOMING_MSG_CMD:</span>//接收数据事件,调用函数AF_DataRequest()接收数据
SampleApp_MessageMSGCB( MSGpkt );//调用回调函数对收到的数据进行处理
break;
// Received whenever the device changes state in the network
case <span style="color:#ff0000;">ZDO_STATE_CHANGE:</span>
//只要网络状态发生改变，就通过ZDO_STATE_CHANGE事件通知所有的任务。
//同时完成对协调器，路由器，终端的设置
SampleApp_NwkState = (devStates_t)(MSGpkt->hdr.status);
//if ( (SampleApp_NwkState == DEV_ZB_COORD)//实验中协调器只接收数据所以取消发送事件
if ( (SampleApp_NwkState == DEV_ROUTER) || (SampleApp_NwkState == DEV_END_DEVICE) )
{
// Start sending the periodic message in a regular interval.
//这个定时器只是为发送周期信息开启的，设备启动初始化后从这里开始
//触发第一个周期信息的发送，然后周而复始下去
osal_start_timerEx( SampleApp_TaskID,
SAMPLEAPP_SEND_PERIODIC_MSG_EVT,
SAMPLEAPP_SEND_PERIODIC_MSG_TIMEOUT );
}
else
{
// Device is no longer in the network
}
break;
default:
break;
}
// Release the memory 事件处理完了，释放消息占用的内存
osal_msg_deallocate( (uint8 *)MSGpkt );
// Next - if one is available 指针指向下一个放在缓冲区的待处理的事件，
//返回while ( MSGpkt )重新处理事件，直到缓冲区没有等待处理事件为止
MSGpkt = (afIncomingMSGPacket_t *)osal_msg_receive( SampleApp_TaskID );
}
// return unprocessed events 返回未处理的事件
return (events ^ SYS_EVENT_MSG);
}
如上，红色标注部分为事件类型，当系统发生该类事件时，会进入该函数，部分事件需要注册，如KEY_CHANGE事件；
暂歇一会，明天继续，，，，，，
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