ZigBee协议栈任务处理分析笔记.doc

ZigBee协议栈任务处理分析笔记 -(转载请注明出处 774910349)Everhuai写于2011-11-17弄了这么久ZigBee协议栈，今天终于有一点头绪了，基本上知道了整个系统任务怎么被添加，又是怎么被切换的一个过程。下面就简单讲一讲这部分内容。首先看的当然是main()函数，不过这个函数不是今天的重点，里面有我添加的注释，先就一笔带过吧。int main( void ) / Turn off interrupts osal_int_disable( INTS_ALL );/关闭全局中断EA=0,初始化过程不响应任何中断 / Initialization for board related stuff such as LEDs HAL_BOARD_INIT();/配置了时钟、LED、串口 / Make sure supply voltage is high enough to run zmain_vdd_check();/检查电源电压 / Initialize stack memory zmain_ram_init();/初始化堆内存 / Initialize board I/O/初始化板子用到的IO口 InitBoard( OB_COLD ); / Initialze HAL drivers HalDriverInit();/初始化外设 / Initialize NV System/系统初始化 osal_nv_init( NULL ); / Initialize basic NV items/任务初始化 zgInit(); / Initialize the MAC ZMacInit(); / Determine the extended address/确定长地址 zmain_ext_addr();#ifndef NONWK / Since the AF isnt a task, call its initialization routine afInit();#endif / Initialize the operating system osal_init_system();/系统初始化 / Allow interrupts osal_int_enable( INTS_ALL );/使能中断 / Final board initialization/后期初始化 InitBoard( OB_READY ); /sd rest / Display information about this device/显示设备信息 zmain_dev_info(); /* Display the device info on the LCD */#ifdef LCD_SUPPORTED zmain_lcd_init();/显示信息#endif#ifdef WDT_IN_PM1 /* If WDT is used, this is a good place to enable it. */ WatchDogEnable( WDTIMX );/使用看门狗#endif osal_start_system(); / No Return from here/正常情况下不返回 / Shouldnt get here return ( 0 ); / main()其中含有osal的都是与操作系统相关的。这里主要提一下这些函数： / Initialze HAL drivers HalDriverInit();/初始化外设片内外设与片外外设基本上在这个函数中初始化，像Timer、DMA、LCD等。该函数调用后设备即可使用。 / Initialize basic NV items zgInit();这个函数通过调用 / Initialize the items table zgInitItems( setDefault );初始化了zgItemTable/ZGlobal Item Table我反正没搞懂这个数组干嘛用的，至少跟我们今天讨论的任务没有关系。我们讨论的任务在 / Initialize the operating system osal_init_system();函数中调用osalInitTasks()进行初始化，在该函数中为每一个任务分配了一个ID号，这个ID号在任务切换的时候将用到。该函数中的初始化函数的顺序与函数指针数组const pTaskEventHandlerFn tasksArr中对应的任务的顺序是一致的，这一点不难理解，就是为了保证任务与ID号的对应。该函数中还有这么两天语句值得注意： tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);/申请空间，用于存放任务 osal_memset( tasksEvents, 0, (sizeof( uint16 ) * tasksCnt);/用0初始化申请到的空间tasksEvents是一个指针，C语言好的不用看它的定义都看得出来。任务切换的时候就是通过tasksEvents来查找需要处理的任务。tasksEvents指向的对象保存的是对应任务的掩码。最后通过调用函数osal_start_system(); /* No Return from here*/启动操作系统，该函数正常情况下是不返回的。#if !defined ( ZBIT ) & !defined ( UBIT ) for(;) / Forever Loop#endif然后所有的任务都在这个for循环中被处理： uint8 idx = 0; osalTimeUpdate();/定时器任务更新/轮询处理 Hal_ProcessPoll(); / This replaces MT_SerialPoll() and osal_check_timer(). do if (tasksEventsidx) / Task is highest priority that is ready./查找优先级最高的任务 break; while (+idx tasksCnt);/tasksCnt为总的任务数 if (idx tasksCnt)/任务数检查 uint16 events; halIntState_t intState; HAL_ENTER_CRITICAL_SECTION(intState);/保存中断状态 events = tasksEventsidx;/取出任务后立即清除 tasksEventsidx = 0; / Clear the Events for this task. HAL_EXIT_CRITICAL_SECTION(intState);/恢复中断状态 events = (tasksArridx)( idx, events );/执行任务,返回值是未处理的事件的掩码 HAL_ENTER_CRITICAL_SECTION(intState); tasksEventsidx |= events; / Add back unprocessed events to the current task./添加未被处理的任务 HAL_EXIT_CRITICAL_SECTION(intState); #if defined( POWER_SAVING ) else / Complete pass through all task events with no activity? /当任务ID号出错时进入睡眠 osal_pwrmgr_powerconserve(); / Put the processor/system into sleep #endif 当有任务需要处理时便调用函数osal_set_event()添加任务：/* * fn osal_set_event * * brief * * This function is called to set the event flags for a task. The * event passed in is ORd into the tasks event variable. *设置事件标志,这些事件保存到变量task * param uint8 task_id - receiving tasks ID * param uint8 event_flag - what event to set * * return SUCCESS, INVALID_TASK */uint8 osal_set_event( uint8 task_id, uint16 event_flag ) if ( task_id timeout timeout = 0; else srchTimer-timeout = srchTimer-timeout - updateTime; / When timeout or delete (event_flag = 0)/需要处理的事件 if ( srchTimer-timeout = 0 | srchTimer-event_flag = 0 ) / Take out of list if ( prevTimer = NULL ) timerHead = srchTimer-next; else prevTimer-next = srchTimer-next; / Setup to free memory/设置要被释放的资源 freeTimer = srchTimer; / Next srchTimer = srchTimer-next; else / Get next/下一个任务 prevTimer = srchTimer; srchTimer = srchTimer-next; HAL_EXIT_CRITICAL_SECTION( intState ); / Re-enable interrupts. if ( freeTimer )/释放任务 if ( freeTimer-timeout = 0 ) osal_set_event( freeTimer-task_id, freeTimer-event_flag );/时间到了，设置事件标志以等待处理 osal_mem_free( freeTimer );/释放该定时器任务的资源 在我所使用的版本中该函数只被两个函数调用，分别是：/* * fn osal_adjust_timers * * brief Update the timer structures for elapsed ticks. * * param none * * return none */void osal_adjust_timers( void ) uint16 eTime; if ( timerHead != NULL ) / Compute elapsed time (msec) eTime = TimerElapsed() / TICK_COUNT; if ( eTime ) osalTimerUpdate( eTime ); /* * FUNCTIONS */* * fn osalTimeUpdate * * brief Uses the free running rollover count of the MAC backoff timer; * this timer runs freely with a constant 320 usec interval. The * count of 320-usec ticks is converted to msecs and used to update * the OSAL clock and Timers by invoking osalClockUpdate() and * osalTimerUpdate(). This function is intended to be invoked * from the background, not interrupt level. * * param None. * * return None. */void osalTimeUpdate( void )/定时器任务更新 uint16 tmp; uint16 ticks320us; uint16 elapsedMSec = 0; / Get the free-running count of 320us timer ticks/设置时间片 tmp = macMcuPrecisionCount();/获取溢出值，该溢出值是一个累计的溢出值 if ( tmp != previousMacTimerTick )/相等则代表没有溢出 / Calculate the elapsed ticks of the free-running timer./计算已经消耗的时间 ticks320us = tmp - previousMacTimerTick; / Store the MAC Timer tick count for the next time through this function. previousMacTimerTick = tmp;/保存当前时间 /* It is necessary to loop to convert the usecs to msecs in increments so as * not to overflow the 16-bit variables. *这是必要的循环转换usecs毫秒的增量，以免溢出16位变量。 */ while ( ticks320us MAXCALCTICKS ) ticks320us -= MAXCALCTICKS; elapsedMSec += MAXCALCTICKS * 8 / 25; remUsTicks += MAXCALCTICKS * 8 % 25; / update converted number with remaining ticks from loop and the / accumulated remainder from loop/更新转换从循环和循环积累的其余部分与其余蜱 tmp = (ticks320us * 8) + remUsTicks; / Convert the 320 us ticks into milliseconds and a remainder elapsedMSec += tmp / 25; remUsTicks = tmp % 25; / Update OSAL Clock and Timers/更新系统定时器 if ( elapsedMSec ) osalClockUpdate( elapsedMSec );/更新系统时间 osalTimerUpdate( elapsedMSec );/更新定时器任务，并设置需要处理的任务的掩码标志 都是跟定时器相关的。在函数osalTimerUpdate开头定义了两个指针： osalTimerRec_t *srchTimer; osalTimerRec_t *prevTimer;其结构osalTimerRec_t定义为typedef struct void *next; uint16 timeout; uint16 event_flag; uint8 task_id; osalTimerRec_t;操作一个单向链表，链表头为timerHead，该链表中保存了所有需要定时执行的任务。这些任务在函数osalTimerRec_t * osalAddTimer( uint8 task_id, uint16 event_flag, uint16 timeout )中被创建。而该函数（只）被uint8 osal_start_timerEx( uint8 taskID, uint16 event_id, uint16 timeout_value )调用uint8 osal_start_timerEx( uint8 taskID, uint16 event_id, uint16 timeout_value ) halIntState_t intState; osalTimerRec_t *newTimer; HAL_ENTER_CRITICAL_SECTION( intState ); / Hold off interrupts./保存中断状态 / Add timer/添加定时器任务 newTimer = osalAddTimer( taskID, event_id , timeout_value ); HAL_EXIT_CRITICAL_SECTION( intState ); / Re-enable interrupts. return ( (newTimer != NULL) ? SUCCESS : NO_TIMER_AVAIL );其中event_id跟函数uint8 osal_set_event( uint8 task_id, uint16 event_flag )中event_flag的作用是一样的，都是最后被写入到tasksEvents中的掩码。通过函数osal_set_event()更改tasksEvents： tasksEventstask_id |= event_flag; / Stuff the event bit(s)/添加需要处理的事件的掩码函数osal_start_timerEx使用结构osalTimerRec_t临时保存newTimer-event_flag = event_flag;最后通过在主循环中调用osalTimeUpdate()又调用osalTimerUpdate( elapsedMSec )最后通过代码 if ( freeTimer )/释放任务 if ( freeTimer-timeout = 0 ) osal_set_event( freeTimer-task_id, freeTimer-event_flag );/时间到了，设置事件标志以等待处理 osal_mem_free( freeTimer );/释放该定时器任务的资源 看到没，最后还是调用函数osal_set_event()对tasksEvents进行更改。当一个任务处理完毕时在主循环中清除相应的掩码。当然当一开始进入函数osal_start_system()中时，应该是没有任务的，这个时候任务是通过中断层层调用，最后还是调用函数osal_set_event()添加任务。在ZigBee协议栈中，中断函数是通过宏来实现的。这些宏在Hal_mcu.h文件中定义：#define _PRAGMA(x) _Pragma(#x)#define HAL_ISR_FUNC_DECLARATION(f,v) _PRAGMA(vector=v) _near_func _interrupt void f(void)#define HAL_ISR_FUNC_PROTOTYPE(f,v) _PRAGMA(vector=v) _near_func _interrupt void f(void)#define HAL_ISR_FUNCTION(f,v) HAL_ISR_FUNC_PROTOTYPE(f,v); HAL_ISR_FUNC_DECLARATION(f,v)当需要编写一个中断函数实体时使用宏HAL_ISR_FUNCTION(f,v)，如：HAL_ISR_FUNCTION( halKeyPort0Isr, P0INT_VECTOR )/P0口中断服务函数 if (HAL_KEY_SW_6_PXIFG & HAL_KEY_SW_6_BIT)|(HAL_KEY_SW_7_PXIFG & HAL_KEY_SW_7_BIT) halProcessKeyInterrupt(); /* Clear the CPU interrupt flag for Port_0 PxIFG has to be cleared before PxIF */ /清除中断标志 HAL_KEY_SW_6_PXIFG = 0; HAL_KEY_CPU_PORT_0_IF = 0;HAL_ISR_FUNCTION( halTimer1Isr, T1_VECTOR )/定时器1中断服务函数 halProcessTimer1 ();HAL_ISR_FUNCTION( macMcuRfIsr, RF_VECTOR )/RF中断服务函数只要对这些宏进行展开就得到了CC2530中断服务函数的形式。下面就通过来看一下中断服务函数是怎么添加任务的。在P0口中断服务函数中调用了这么一个函数halProcessKeyInterrupt(),该函数的实现如下：/* * fn halProcessKeyInterrupt * * brief Checks to see if its a valid key interrupt, saves interrupt driven key states for * processing by HalKeyRead(), and debounces keys by scheduling HalKeyRead() 25ms later. * * param * * return */void halProcessKeyInterrupt (void) bool valid=FALSE;/检查中断源 if (HAL_KEY_SW_6_PXIFG & HAL_KEY_SW_6_BIT) /* Interrupt Flag has been set */ HAL_KEY_SW_6_PXIFG = (HAL_KEY_SW_6_BIT); /* Clear Interrupt Flag */ valid = TRUE; if (HAL_KEY_SW_7_PXIFG & HAL_KEY_SW_7_BIT) /* Interrupt Flag has been set */ HAL_KEY_SW_7_PXIFG = (HAL_KEY_SW_7_BIT); /* Clear Interrupt Flag */ valid = TRUE; if (HAL_KEY_JOY_MOVE_PXIFG & HAL_KEY_JOY_MOVE_BIT) /* Interrupt Flag has been set */ HAL_KEY_JOY_MOVE_PXIFG = (HAL_KEY_JOY_MOVE_B