zigbee协议与开发－ZStack协议栈结构的初步解析 - 中科因仑“3+1”工程特种兵精英论坛

在阅读了Zigbee及IEEE802.15.4协议的理论知识后，接下来看一下TI公司开发的基于Zigbee的协议实现ZStack。

我们仍然从TI提供的温度监测程序开始，首先查看一下，程序的主函数在ZMain.c文件中,从程序的说明看出,是ZStack的startup和shutdown代码.

以下是其中的main()函数，其实英文注释已经很清楚说明每一步，这里翻译一下:

int main( void )
{
// Turn off interrupts(关中断)
osal_int_disable( INTS_ALL );
// Initialization for board related stuff such as LEDs(初始化板上组件，如LED)
HAL_BOARD_INIT();
// Make sure supply voltage is high enough to run（电压检查）
zmain_vdd_check();
// Initialize board I/O（初始化I/O接口）
InitBoard( OB_COLD );
// Initialze HAL drivers(初始化HAL设备，在hal_drivers.c中实现)
HalDriverInit();
// Initialize NV System(初始化NV系统，即非易失设备，如Flash)
osal_nv_init( NULL );
// Initialize the MAC（初始化MAC）
ZMacInit();
// Determine the extended address（确定设备的长地址）
zmain_ext_addr();
// Initialize basic NV items(初始化ZStack的全局变量，如果在NV内存中不存在，则写入缺省值)
zgInit();
#ifndef NONWK
// Since the AF isn't a task, call it's initialization routine
afInit();
#endif
// Initialize the operating system(初始化操作系统)
osal_init_system();
// Allow interrupts（开中断）
osal_int_enable( INTS_ALL );
// Final board initialization（最后初始化板）
InitBoard( OB_READY );
// Display information about this device（显示设备信息，比如CollectorEB板的IEEE地址就是在这个函数里面显示出来的。）
zmain_dev_info();
/* Display the device info on the LCD */（显示LCD设备信息）
#ifdef LCD_SUPPORTED
zmain_lcd_init();
#endif
#ifdef WDT_IN_PM1
/* If WDT is used, this is a good place to enable it. */（开WatchDog）
WatchDogEnable( WDTIMX );
#endif
osal_start_system(); // No Return from here（启动操作系统，实际上进入一个死循环）
return 0; // Shouldn't get here.
} // main()

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说明：以上初始化有的跟硬件相关，有的跟操作系统(以osal开头)相关，最后系统调用osal_start_system进入循环，然后在循环中处理消息，下面是这个函数的主体（见osal.c）：

void osal_start_system( void )
{
#if !defined ( ZBIT ) && !defined ( UBIT )
for(;;) // Forever Loop (死循环)
#endif
{
uint8 idx = 0;
osalTimeUpdate(); //更新时间
Hal_ProcessPoll(); // This replaces MT_SerialPoll() and osal_check_timer().（轮询UART和Timer等设备消息）
do {
if (tasksEvents[idx]) // Task is highest priority that is ready.
{
break;
}
} while (++idx < tasksCnt);
if (idx < tasksCnt)
{
uint16 events;
halIntState_t intState;
HAL_ENTER_CRITICAL_SECTION(intState); //加锁防上访问事件队列充突
events = tasksEvents[idx];
tasksEvents[idx] = 0; // Clear the Events for this task.
HAL_EXIT_CRITICAL_SECTION(intState);
events = (tasksArr[idx])( idx, events ); //处理当前要处理的事件，并返回事件ID
HAL_ENTER_CRITICAL_SECTION(intState);
tasksEvents[idx] |= events; // Add back unprocessed events to the current task.(更新事件状态)
HAL_EXIT_CRITICAL_SECTION(intState);
}
#if defined( POWER_SAVING )
else // Complete pass through all task events with no activity?
{
osal_pwrmgr_powerconserve(); // Put the processor/system into sleep(没有事件处理，进入休眠状态)
}
#endif
}
}

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需要特别解析的是上面红色标注的行，这个地方看起来象是一个函数指针的形式，查看taskArr定义（见SAPI.c）如下：

#if OSAL_SAPI
// The order in this table must be identical to the task initialization calls below inosalInitTask.
const pTaskEventHandlerFn tasksArr[] = {
macEventLoop,
nwk_event_loop,
Hal_ProcessEvent,
#if defined( MT_TASK )
MT_ProcessEvent,
#endif
APS_event_loop,
ZDApp_event_loop,
SAPI_ProcessEvent
};

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extern uint16 macEventLoop(uint8 taskId, uint16 events);

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UINT16 SAPI_ProcessEvent( byte task_id, UINT16 events )
{
osal_event_hdr_t *pMsg;
afIncomingMSGPacket_t *pMSGpkt;
afDataConfirm_t *pDataConfirm;
if ( events & SYS_EVENT_MSG ) //系统事件消息，只有定义了SAPI_CB_FUNC 的似乎才会被上层应用处理。
{
...
case KEY_CHANGE:
#if ( SAPI_CB_FUNC )
zb_HandleKeys( ((keyChange_t *)pMsg)->state, ((keyChange_t *)pMsg)->keys );
#endif
break;
...
// Return unprocessed events
return (events ^ SYS_EVENT_MSG);
}
if ( events & ZB_ALLOW_BIND_TIMER ) //ZB_ALLOW_BIND_TIMER
{
afSetMatch(sapi_epDesc.simpleDesc->EndPoint, FALSE);
return (events ^ ZB_ALLOW_BIND_TIMER);
}
if ( events & ZB_BIND_TIMER ) //ZB_BIND_TIMER
{
// Send bind confirm callback to application
SAPI_BindConfirm( sapi_bindInProgress, ZB_TIMEOUT );
sapi_bindInProgress = 0xffff;
return (events ^ ZB_BIND_TIMER);
}
if ( events & ZB_ENTRY_EVENT ) //ZB_ENTRY_EVENT
{
uint8 startOptions;
// Give indication to application of device startup
#if ( SAPI_CB_FUNC )
zb_HandleOsalEvent( ZB_ENTRY_EVENT );
#endif
// LED off cancels HOLD_AUTO_START blink set in the stack
HalLedSet (HAL_LED_4, HAL_LED_MODE_OFF);
zb_ReadConfiguration( ZCD_NV_STARTUP_OPTION, sizeof(uint8), &startOptions );
if ( startOptions & ZCD_STARTOPT_AUTO_START )
{
zb_StartRequest();
}
else
{
// blink leds and wait for external input to config and restart
HalLedBlink(HAL_LED_2, 0, 50, 500);
}
return (events ^ ZB_ENTRY_EVENT );
}
// This must be the last event to be processed
if ( events & ( ZB_USER_EVENTS ) )
{
// User events are passed to the application
#if ( SAPI_CB_FUNC )
zb_HandleOsalEvent( events );
#endif
// Do not return here, return 0 later
}
// Discard unknown events
return 0;
}

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void zb_HandleKeys( uint8 shift, uint8 keys )
{
static uint8 allowBind=FALSE;
static uint8 allowJoin=TRUE;
uint8 logicalType;
// Shift is used to make each button/switch dual purpose.
if ( shift )
{
if ( keys & HAL_KEY_SW_1 )
{
}
if ( keys & HAL_KEY_SW_2 )
{
}
if ( keys & HAL_KEY_SW_3 )
{
}
if ( keys & HAL_KEY_SW_4 )
{
}
}
else
{
if ( keys & HAL_KEY_SW_1 ) //Joystick Up key (Set as cordinator，设置为协调器)
{
if ( appState == APP_INIT )
{
// Key 1 starts device as a coordinator
logicalType = ZG_DEVICETYPE_COORDINATOR;
zb_WriteConfiguration(ZCD_NV_LOGICAL_TYPE, sizeof(uint8), &logicalType);
// Reset the device with new configuration
zb_SystemReset();
}
}
if ( keys & HAL_KEY_SW_2 ) //Joystick Right key (Allow bind，允许绑定，一个网络中只有一个节点，即协调器有此设置。)
{
allowBind ^= 1;
if (allowBind)
{
// Turn ON Allow Bind mode infinitly
zb_AllowBind( 0xFF );
HalLedSet( HAL_LED_2, HAL_LED_MODE_ON );
//This node is the gateway node
isGateWay = TRUE;
// Update the display
#if defined ( LCD_SUPPORTED )
HalLcdWriteString( "Gateway Mode", HAL_LCD_LINE_2 );
#endif
}
else
{
// Turn OFF Allow Bind mode infinitly
zb_AllowBind( 0x00 );
HalLedSet( HAL_LED_2, HAL_LED_MODE_OFF );
isGateWay = FALSE;
// Update the display
#if defined ( LCD_SUPPORTED )
HalLcdWriteString( "Collector", HAL_LCD_LINE_2 );
#endif
}
}
if ( keys & HAL_KEY_SW_3 ) //Joystick down key(路由器有效，用于定时向协调器报告事件，以生成拓扑图)
{
// Start reporting
osal_set_event( sapi_TaskID, MY_REPORT_EVT );
}
if ( keys & HAL_KEY_SW_4 ) //Joystick Left key(用于禁止/允许节点加入，此功能用于协调器设置禁止或允许节点加入，但是不知为何无效！！？)
{
// Key 4 is used to control which routers
// that can accept join requests
allowJoin ^= 1;
if(allowJoin)
{
NLME_PermitJoiningRequest(0xFF);
}
else {
NLME_PermitJoiningRequest(0);
}
}
}
}

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void zb_HandleOsalEvent( uint16 event )
{
uint8 logicalType;
if(event & SYS_EVENT_MSG) //系统消息，多数在底层已经处理，因此此处为空。
{
}
if( event & ZB_ENTRY_EVENT ) //系统启动事件，需要做一些设置。
{
// Initialise UART
initUart(uartRxCB);
// blind LED 1 to indicate starting/joining a network
HalLedBlink ( HAL_LED_1, 0, 50, 500 );
HalLedSet( HAL_LED_2, HAL_LED_MODE_OFF );
// Read logical device type from NV
zb_ReadConfiguration(ZCD_NV_LOGICAL_TYPE, sizeof(uint8), &logicalType);
// Start the device
zb_StartRequest();
}
if ( event & MY_START_EVT )
{
zb_StartRequest();
}
if ( event & MY_REPORT_EVT )
{
if (isGateWay)
{
osal_start_timerEx( sapi_TaskID, MY_REPORT_EVT, myReportPeriod );
}
else if (appState == APP_BINDED)
{
sendDummyReport();
osal_start_timerEx( sapi_TaskID, MY_REPORT_EVT, myReportPeriod );
}
}
if ( event & MY_FIND_COLLECTOR_EVT )
{
// Find and bind to a gateway device (if this node is not gateway)
if (!isGateWay)
{
zb_BindDevice( TRUE, DUMMY_REPORT_CMD_ID, (uint8 *)NULL );
}
}
}

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