TI-BLE 协议栈（CC2541）peripheral的执行流程分析

BLE 技术是 Bluetooth SIG 规定的一套通信协议，在协议变成具体的代码之前，都只存在文档中， TI、 Nordic、 CSR 等厂商，根据 SIG 发布的 BLE 技术协议，配合自身的芯片开发了一整套源码，并且这套源码经过了 SIG 的测试，服务 BLE 协议。这套源码就叫做协议栈，协议栈是协议的实现。不同的芯片厂商都有各自的协议栈，而这不同的协议栈， Bluetooth SIG 是不允许厂商开源的，所以，无论是TI的或者NORDIC的BLE芯片资料中协议栈都是做成库的形式提供，只开放部分的API层。
分析的使用 TI 的 BLE 协议栈 1.3.2 版本，其他更新的版本，也是同样的结构的。

一、BLE 协议栈 OSAL

BLE 协议栈包含了 BLE 协议所规定的基本功能，这些功能是以函数的形式实现的，为了便于管理这些函数集， BLE 协议栈内称为 OSAL (操作系统抽象层Operating SystemAbstraction Layer)。
OSAL 就是一种支持多任务运行的系统资源分配机制。OSAL 建立事件和任务的时间处理的联系方法是：建议一个事件表，保存各个任务的对应的时间，建立另一个函数，保存每个任务函数的地址，然后将这两张表建立某种对应关系，当某一时间发生时，则查找函数表，找到对应的任务函数的指针，然后通过函数指针，调用该函数即可。
BLE 协议栈 OSAL主要应用在四个文件内。OSAL_SimpleBLEPeripheral.c ， simpleBLEPeripheral.c ， simpleBLEPeripheral.h ，
SimpleBLEPeripheral_Main.c 整个程序所实现的功能都包含在这四个源文件中。

二、BLE 协议栈执行流程

SimpleBLEPeripheral_Main.c 文件，打开该文件可以找到 main()函数，这就是整个协议栈的入口点，即从该函数开始执行。

/*************************************************************************************************** @fn          main** @brief       Start of application.** @param       none** @return      none***************************************************************************************************/
int main(void)
{/* Initialize hardware */HAL_BOARD_INIT();// Initialize board I/OInitBoard( OB_COLD );/* Initialze the HAL driver */HalDriverInit();/* Initialize NV system */osal_snv_init();/* Initialize LL *//* Initialize the operating system */osal_init_system();/* Enable interrupts */HAL_ENABLE_INTERRUPTS();// Final board initializationInitBoard( OB_READY );#if defined ( POWER_SAVING )osal_pwrmgr_device( PWRMGR_BATTERY );#endif/* Start OSAL */osal_start_system(); // No Return from herereturn 0;
}

函数osal_init_system();执行的是OSAL系统的初始化，
函数osal_start_system();就是开始OSAL系统

2.1、OSAL系统的初始化

打开 OSAL.c 文件的uint8 osal_init_system( void )。

/********************************************************************** @fn      osal_init_system** @brief**   This function initializes the "task" system by creating the*   tasks defined in the task table (OSAL_Tasks.h).** @param   void** @return  SUCCESS*/
uint8 osal_init_system( void )
{#if !defined USE_ICALL && !defined OSAL_PORT2TIRTOS// Initialize the Memory Allocation Systemosal_mem_init();
#endif /* !defined USE_ICALL && !defined OSAL_PORT2TIRTOS */// Initialize the message queueosal_qHead = NULL;// Initialize the timersosalTimerInit();// Initialize the Power Management Systemosal_pwrmgr_init();#ifdef USE_ICALL/* Prepare memory space for service enrollment */osal_prepare_svc_enroll();
#endif /* USE_ICALL */// Initialize the system tasks.osalInitTasks();#if !defined USE_ICALL && !defined OSAL_PORT2TIRTOS// Setup efficient search for the first free block of heap.osal_mem_kick();
#endif /* !defined USE_ICALL && !defined OSAL_PORT2TIRTOS */#ifdef USE_ICALL// Initialize variables used to track timing and provide OSAL timer serviceosal_last_timestamp = (uint_least32_t) ICall_getTicks();osal_tickperiod = (uint_least32_t) ICall_getTickPeriod();osal_max_msecs = (uint_least32_t) ICall_getMaxMSecs();/* Reduce ceiling considering potential latency */osal_max_msecs -= 2;
#endif /* USE_ICALL */return ( SUCCESS );
}

其中 osalInitTasks();就是初始化系统任务。打开OSAL_SimpleBLEPeripheral.c文件找到：

/********************************************************************** GLOBAL VARIABLES*/// The order in this table must be identical to the task initialization calls below in osalInitTask.
const pTaskEventHandlerFn tasksArr[] =
{LL_ProcessEvent,                                                  // task 0Hal_ProcessEvent,                                                 // task 1HCI_ProcessEvent,                                                 // task 2
#if defined ( OSAL_CBTIMER_NUM_TASKS )OSAL_CBTIMER_PROCESS_EVENT( osal_CbTimerProcessEvent ),           // task 3
#endifL2CAP_ProcessEvent,                                               // task 4GAP_ProcessEvent,                                                 // task 5SM_ProcessEvent,                                                  // task 6GATT_ProcessEvent,                                                // task 7GAPRole_ProcessEvent,                                             // task 8GAPBondMgr_ProcessEvent,                                          // task 9GATTServApp_ProcessEvent,                                         // task 10SimpleBLEPeripheral_ProcessEvent                                  // task 11
};const uint8 tasksCnt = sizeof( tasksArr ) / sizeof( tasksArr[0] );
uint16 *tasksEvents;/********************************************************************** FUNCTIONS*********************************************************************//********************************************************************** @fn      osalInitTasks** @brief   This function invokes the initialization function for each task.** @param   void** @return  none*/
void osalInitTasks( void )
{uint8 taskID = 0;tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);osal_memset( tasksEvents, 0, (sizeof( uint16 ) * tasksCnt));/* LL Task */LL_Init( taskID++ );/* Hal Task */Hal_Init( taskID++ );/* HCI Task */HCI_Init( taskID++ );#if defined ( OSAL_CBTIMER_NUM_TASKS )/* Callback Timer Tasks */osal_CbTimerInit( taskID );taskID += OSAL_CBTIMER_NUM_TASKS;
#endif/* L2CAP Task */L2CAP_Init( taskID++ );/* GAP Task */GAP_Init( taskID++ );/* SM Task */SM_Init( taskID++ );/* GATT Task */GATT_Init( taskID++ );/* Profiles */GAPRole_Init( taskID++ );GAPBondMgr_Init( taskID++ );GATTServApp_Init( taskID++ );/* Application */SimpleBLEPeripheral_Init( taskID );
}

tasksArr数组，定义了各个人物的处理函数，这些任何函数，就是 osal 所谓的“多任务” 处理函数，其中SimpleBLEPeripheral_ProcessEvent 就是从机的应用任务处理函数。

  tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);osal_memset( tasksEvents, 0, (sizeof( uint16 ) * tasksCnt));

这里对任务个数经行了赋值，并且开辟了任务的事件内存。
接下来是逐个任务的初始化，SimpleBLEPeripheral_Init( taskID )是对应用任务的初始化。

2.2、OSAL系统的执行

OSAL系统的执行函数 osal_start_system(); 定义在 OSAL.c 文件中

/********************************************************************** @fn      osal_start_system** @brief**   This function is the main loop function of the task system (if*   ZBIT and UBIT are not defined). This Function doesn't return.** @param   void** @return  none*/
void osal_start_system( void )
{#ifdef USE_ICALL/* Kick off timer service in order to allocate resources upfront.* The first timeout is required to schedule next OSAL timer event* as well. */ICall_Errno errno = ICall_setTimer(1, osal_msec_timer_cback,(void *) osal_msec_timer_seq,&osal_timerid_msec_timer);if (errno != ICALL_ERRNO_SUCCESS){ICall_abort();}
#endif /* USE_ICALL */#if !defined ( ZBIT ) && !defined ( UBIT )for(;;)  // Forever Loop
#endif{osal_run_system();#ifdef USE_ICALLICall_wait(ICALL_TIMEOUT_FOREVER);
#endif /* USE_ICALL */}
}

其中osal_run_system();进入任务函数的循环。

/********************************************************************** @fn      osal_run_system** @brief**   This function will make one pass through the OSAL taskEvents table*   and call the task_event_processor() function for the first task that*   is found with at least one event pending. If there are no pending*   events (all tasks), this function puts the processor into Sleep.** @param   void** @return  none*/
void osal_run_system( void )
{uint8 idx = 0;#ifdef USE_ICALLuint32 next_timeout_prior = osal_next_timeout();
#else /* USE_ICALL */
#ifndef HAL_BOARD_CC2538osalTimeUpdate();
#endifHal_ProcessPoll();
#endif /* USE_ICALL */#ifdef USE_ICALL{/* Update osal timers to the latest before running any OSAL processes* regardless of wakeup callback from ICall because OSAL timers are added* relative to the current time. */unsigned long newtimestamp = ICall_getTicks();uint32 milliseconds;if (osal_tickperiod == 1000){milliseconds = newtimestamp - osal_last_timestamp;osal_last_timestamp = newtimestamp;}else{unsigned long long delta = (unsigned long long)((newtimestamp - osal_last_timestamp) & 0xfffffffful);delta *= osal_tickperiod;delta /= 1000;milliseconds = (uint32) delta;osal_last_timestamp += (uint32) (delta * 1000 / osal_tickperiod);}osalAdjustTimer(milliseconds);/* Set a value that will never match osal_next_timeout()* return value so that the next time can be scheduled.*/next_timeout_prior = 0xfffffffful;}if (osal_eventloop_hook){osal_eventloop_hook();}for (;;){void *msg;ICall_EntityID src, dst;osal_msg_hdr_t *hdr;uint8 dest_id;if (ICall_fetchMsg(&src, &dst, &msg) != ICALL_ERRNO_SUCCESS){break;}hdr = (osal_msg_hdr_t *) msg - 1;dest_id = osal_dispatch2id(dst);if (dest_id == TASK_NO_TASK){/* Something wrong */ICall_abort();}else{/* Message towards one of the tasks *//* Create a proxy task ID if necessary and* queue the message to the OSAL internal queue.*/uint8 proxyid = osal_alien2proxy(hdr->srcentity);if (hdr->format == ICALL_MSG_FORMAT_1ST_CHAR_TASK_ID){uint8 *bytes = msg;*bytes = proxyid;}else if (hdr->format == ICALL_MSG_FORMAT_3RD_CHAR_TASK_ID){uint8 *bytes = msg;bytes[2] = proxyid;}/* now queue the message to the OSAL queue */osal_msg_send(dest_id, msg);}}
#endif /* USE_ICALL */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);events = tasksEvents[idx];tasksEvents[idx] = 0;  // Clear the Events for this task.HAL_EXIT_CRITICAL_SECTION(intState);activeTaskID = idx;events = (tasksArr[idx])( idx, events );activeTaskID = TASK_NO_TASK;HAL_ENTER_CRITICAL_SECTION(intState);tasksEvents[idx] |= events;  // Add back unprocessed events to the current task.HAL_EXIT_CRITICAL_SECTION(intState);}
#if defined( POWER_SAVING ) && !defined(USE_ICALL)else  // Complete pass through all task events with no activity?{osal_pwrmgr_powerconserve();  // Put the processor/system into sleep}
#endif/* Yield in case cooperative scheduling is being used. */
#if defined (configUSE_PREEMPTION) && (configUSE_PREEMPTION == 0){osal_task_yield();}
#endif#if defined USE_ICALL/* Note that scheduling wakeup at this point instead of* scheduling it upon ever OSAL start timer request,* would only work if OSAL start timer call is made* from OSAL tasks, but not from either ISR or* non-OSAL application thread.* In case, OSAL start timer is called from non-OSAL* task, the scheduling should be part of OSAL_Timers* module.* Such a change to OSAL_Timers module was not made* in order not to diverge the OSAL implementations* too drastically between pure OSAL solution vs.* OSAL upon service dispatcher (RTOS).* TODO: reconsider the above statement.*/{halIntState_t intState;uint32 next_timeout_post = osal_next_timeout();if (next_timeout_post != next_timeout_prior){/* Next wakeup time has to be scheduled */if (next_timeout_post == 0){/* No timer. Set time to the max */next_timeout_post = OSAL_TIMERS_MAX_TIMEOUT;}if (next_timeout_post > osal_max_msecs){next_timeout_post = osal_max_msecs;}/* Restart timer */HAL_ENTER_CRITICAL_SECTION(intState);ICall_stopTimer(osal_timerid_msec_timer);ICall_setTimerMSecs(next_timeout_post, osal_msec_timer_cback,(void *) (++osal_msec_timer_seq),&osal_timerid_msec_timer);HAL_EXIT_CRITICAL_SECTION(intState);}}
#endif /* USE_ICALL */
}

在 osal_run_system() 函数中，每次循环前都会判断tasksEvents，代码流程图如下：

三、BLE的 peripheral 从机工程

在OSAL系统的初始化的时候在tasksArr任务指针数组中定义了一个SimpleBLEPeripheral_ProcessEvent任务，且调用了SimpleBLEPeripheral_Init( taskID )。SimpleBLEPeripheral_Init 是任务的初始化函数， SimpleBLEPeripheral_ProcessEvent是从机工程的任务函数。

3.1、 peripheral 从机工程的初始化

SimpleBLEPeripheral_Init 从机工程的初始化函数如下：

/********************************************************************** @fn      SimpleBLEPeripheral_Init** @brief   Initialization function for the Simple BLE Peripheral App Task.*          This is called during initialization and should contain*          any application specific initialization (ie. hardware*          initialization/setup, table initialization, power up*          notificaiton ... ).** @param   task_id - the ID assigned by OSAL.  This ID should be*                    used to send messages and set timers.** @return  none*/
void SimpleBLEPeripheral_Init( uint8 task_id )
{simpleBLEPeripheral_TaskID = task_id;// Setup the GAPVOID GAP_SetParamValue( TGAP_CONN_PAUSE_PERIPHERAL, DEFAULT_CONN_PAUSE_PERIPHERAL );// Setup the GAP Peripheral Role Profile{#if defined( CC2540_MINIDK )// For the CC2540DK-MINI keyfob, device doesn't start advertising until button is presseduint8 initial_advertising_enable = FALSE;#else// For other hardware platforms, device starts advertising upon initializationuint8 initial_advertising_enable = TRUE;#endif// By setting this to zero, the device will go into the waiting state after// being discoverable for 30.72 second, and will not being advertising again// until the enabler is set back to TRUEuint16 gapRole_AdvertOffTime = 0;uint8 enable_update_request = DEFAULT_ENABLE_UPDATE_REQUEST;uint16 desired_min_interval = DEFAULT_DESIRED_MIN_CONN_INTERVAL;uint16 desired_max_interval = DEFAULT_DESIRED_MAX_CONN_INTERVAL;uint16 desired_slave_latency = DEFAULT_DESIRED_SLAVE_LATENCY;uint16 desired_conn_timeout = DEFAULT_DESIRED_CONN_TIMEOUT;// Set the GAP Role ParametersGAPRole_SetParameter( GAPROLE_ADVERT_ENABLED, sizeof( uint8 ), &initial_advertising_enable );GAPRole_SetParameter( GAPROLE_ADVERT_OFF_TIME, sizeof( uint16 ), &gapRole_AdvertOffTime );GAPRole_SetParameter( GAPROLE_SCAN_RSP_DATA, sizeof ( scanRspData ), scanRspData );GAPRole_SetParameter( GAPROLE_ADVERT_DATA, sizeof( advertData ), advertData );GAPRole_SetParameter( GAPROLE_PARAM_UPDATE_ENABLE, sizeof( uint8 ), &enable_update_request );GAPRole_SetParameter( GAPROLE_MIN_CONN_INTERVAL, sizeof( uint16 ), &desired_min_interval );GAPRole_SetParameter( GAPROLE_MAX_CONN_INTERVAL, sizeof( uint16 ), &desired_max_interval );GAPRole_SetParameter( GAPROLE_SLAVE_LATENCY, sizeof( uint16 ), &desired_slave_latency );GAPRole_SetParameter( GAPROLE_TIMEOUT_MULTIPLIER, sizeof( uint16 ), &desired_conn_timeout );}// Set the GAP CharacteristicsGGS_SetParameter( GGS_DEVICE_NAME_ATT, GAP_DEVICE_NAME_LEN, attDeviceName );// Set advertising interval{uint16 advInt = DEFAULT_ADVERTISING_INTERVAL;GAP_SetParamValue( TGAP_LIM_DISC_ADV_INT_MIN, advInt );GAP_SetParamValue( TGAP_LIM_DISC_ADV_INT_MAX, advInt );GAP_SetParamValue( TGAP_GEN_DISC_ADV_INT_MIN, advInt );GAP_SetParamValue( TGAP_GEN_DISC_ADV_INT_MAX, advInt );}// Setup the GAP Bond Manager{uint32 passkey = 0; // passkey "000000"uint8 pairMode = GAPBOND_PAIRING_MODE_WAIT_FOR_REQ;uint8 mitm = TRUE;uint8 ioCap = GAPBOND_IO_CAP_DISPLAY_ONLY;uint8 bonding = TRUE;GAPBondMgr_SetParameter( GAPBOND_DEFAULT_PASSCODE, sizeof ( uint32 ), &passkey );GAPBondMgr_SetParameter( GAPBOND_PAIRING_MODE, sizeof ( uint8 ), &pairMode );GAPBondMgr_SetParameter( GAPBOND_MITM_PROTECTION, sizeof ( uint8 ), &mitm );GAPBondMgr_SetParameter( GAPBOND_IO_CAPABILITIES, sizeof ( uint8 ), &ioCap );GAPBondMgr_SetParameter( GAPBOND_BONDING_ENABLED, sizeof ( uint8 ), &bonding );}// Initialize GATT attributesGGS_AddService( GATT_ALL_SERVICES );            // GAPGATTServApp_AddService( GATT_ALL_SERVICES );    // GATT attributesDevInfo_AddService();                           // Device Information ServiceSimpleProfile_AddService( GATT_ALL_SERVICES );  // Simple GATT Profile
#if defined FEATURE_OADVOID OADTarget_AddService();                    // OAD Profile
#endif// Setup the SimpleProfile Characteristic Values{uint8 charValue1 = 1;uint8 charValue2 = 2;uint8 charValue3 = 3;uint8 charValue4 = 4;uint8 charValue5[SIMPLEPROFILE_CHAR5_LEN] = { 1, 2, 3, 4, 5 };SimpleProfile_SetParameter( SIMPLEPROFILE_CHAR1, sizeof ( uint8 ), &charValue1 );SimpleProfile_SetParameter( SIMPLEPROFILE_CHAR2, sizeof ( uint8 ), &charValue2 );SimpleProfile_SetParameter( SIMPLEPROFILE_CHAR3, sizeof ( uint8 ), &charValue3 );SimpleProfile_SetParameter( SIMPLEPROFILE_CHAR4, sizeof ( uint8 ), &charValue4 );SimpleProfile_SetParameter( SIMPLEPROFILE_CHAR5, SIMPLEPROFILE_CHAR5_LEN, charValue5 );}#if defined( CC2540_MINIDK )SK_AddService( GATT_ALL_SERVICES ); // Simple Keys Profile// Register for all key events - This app will handle all key eventsRegisterForKeys( simpleBLEPeripheral_TaskID );// makes sure LEDs are offHalLedSet( (HAL_LED_1 | HAL_LED_2), HAL_LED_MODE_OFF );// For keyfob board set GPIO pins into a power-optimized state// Note that there is still some leakage current from the buzzer,// accelerometer, LEDs, and buttons on the PCB.P0SEL = 0; // Configure Port 0 as GPIOP1SEL = 0; // Configure Port 1 as GPIOP2SEL = 0; // Configure Port 2 as GPIOP0DIR = 0xFC; // Port 0 pins P0.0 and P0.1 as input (buttons),// all others (P0.2-P0.7) as outputP1DIR = 0xFF; // All port 1 pins (P1.0-P1.7) as outputP2DIR = 0x1F; // All port 1 pins (P2.0-P2.4) as outputP0 = 0x03; // All pins on port 0 to low except for P0.0 and P0.1 (buttons)P1 = 0;   // All pins on port 1 to lowP2 = 0;   // All pins on port 2 to low#endif // #if defined( CC2540_MINIDK )#if (defined HAL_LCD) && (HAL_LCD == TRUE)#if defined FEATURE_OAD#if defined (HAL_IMAGE_A)HalLcdWriteStringValue( "BLE Peri-A", OAD_VER_NUM( _imgHdr.ver ), 16, HAL_LCD_LINE_1 );#elseHalLcdWriteStringValue( "BLE Peri-B", OAD_VER_NUM( _imgHdr.ver ), 16, HAL_LCD_LINE_1 );#endif // HAL_IMAGE_A
#elseHalLcdWriteString( "BLE Peripheral", HAL_LCD_LINE_1 );
#endif // FEATURE_OAD#endif // (defined HAL_LCD) && (HAL_LCD == TRUE)// Register callback with SimpleGATTprofileVOID SimpleProfile_RegisterAppCBs( &simpleBLEPeripheral_SimpleProfileCBs );// Enable clock divide on halt// This reduces active current while radio is active and CC254x MCU// is haltedHCI_EXT_ClkDivOnHaltCmd( HCI_EXT_ENABLE_CLK_DIVIDE_ON_HALT );#if defined ( DC_DC_P0_7 )// Enable stack to toggle bypass control on TPS62730 (DC/DC converter)HCI_EXT_MapPmIoPortCmd( HCI_EXT_PM_IO_PORT_P0, HCI_EXT_PM_IO_PORT_PIN7 );#endif // defined ( DC_DC_P0_7 )// Setup a delayed profile startuposal_set_event( simpleBLEPeripheral_TaskID, SBP_START_DEVICE_EVT );}

SimpleBLEPeripheral_Init函数首先设置GAP协议栈，例如设置为从角色，设置GAP层的Characteristics，然后初始化GATT协议栈，例如设置GATT属性，设置GATT的特征值。
再然后注册从角色的回调函数VOID SimpleProfile_RegisterAppCBs( &simpleBLEPeripheral_SimpleProfileCBs )。
最后产生一个启动事件osal_set_event( simpleBLEPeripheral_TaskID, SBP_START_DEVICE_EVT )
回调函数void simpleProfileChangeCB( uint8 paramID )定义如下：

/********************************************************************** @fn      simpleProfileChangeCB** @brief   Callback from SimpleBLEProfile indicating a value change** @param   paramID - parameter ID of the value that was changed.** @return  none*/
static void simpleProfileChangeCB( uint8 paramID )
{uint8 newValue;switch( paramID ){case SIMPLEPROFILE_CHAR1:SimpleProfile_GetParameter( SIMPLEPROFILE_CHAR1, &newValue );#if (defined HAL_LCD) && (HAL_LCD == TRUE)HalLcdWriteStringValue( "Char 1:", (uint16)(newValue), 10,  HAL_LCD_LINE_3 );#endif // (defined HAL_LCD) && (HAL_LCD == TRUE)break;case SIMPLEPROFILE_CHAR3:SimpleProfile_GetParameter( SIMPLEPROFILE_CHAR3, &newValue );#if (defined HAL_LCD) && (HAL_LCD == TRUE)HalLcdWriteStringValue( "Char 3:", (uint16)(newValue), 10,  HAL_LCD_LINE_3 );#endif // (defined HAL_LCD) && (HAL_LCD == TRUE)break;default:// should not reach here!break;}
}

该函数就是从机接收数据的入口。

3.2、 peripheral 从机工程的任务函数

任务函数代码如下：

/********************************************************************** @fn      SimpleBLEPeripheral_ProcessEvent** @brief   Simple BLE Peripheral Application Task event processor.  This function*          is called to process all events for the task.  Events*          include timers, messages and any other user defined events.** @param   task_id  - The OSAL assigned task ID.* @param   events - events to process.  This is a bit map and can*                   contain more than one event.** @return  events not processed*/
uint16 SimpleBLEPeripheral_ProcessEvent( uint8 task_id, uint16 events )
{VOID task_id; // OSAL required parameter that isn't used in this functionif ( events & SYS_EVENT_MSG ){uint8 *pMsg;if ( (pMsg = osal_msg_receive( simpleBLEPeripheral_TaskID )) != NULL ){simpleBLEPeripheral_ProcessOSALMsg( (osal_event_hdr_t *)pMsg );// Release the OSAL messageVOID osal_msg_deallocate( pMsg );}// return unprocessed eventsreturn (events ^ SYS_EVENT_MSG);}if ( events & SBP_START_DEVICE_EVT ){// Start the DeviceVOID GAPRole_StartDevice( &simpleBLEPeripheral_PeripheralCBs );// Start Bond ManagerVOID GAPBondMgr_Register( &simpleBLEPeripheral_BondMgrCBs );// Set timer for first periodic eventosal_start_timerEx( simpleBLEPeripheral_TaskID, SBP_PERIODIC_EVT, SBP_PERIODIC_EVT_PERIOD );return ( events ^ SBP_START_DEVICE_EVT );}if ( events & SBP_PERIODIC_EVT ){// Restart timerif ( SBP_PERIODIC_EVT_PERIOD ){osal_start_timerEx( simpleBLEPeripheral_TaskID, SBP_PERIODIC_EVT, SBP_PERIODIC_EVT_PERIOD );}// Perform periodic application taskperformPeriodicTask();return (events ^ SBP_PERIODIC_EVT);}// Discard unknown eventsreturn 0;
}

任务函数首先通过osal_msg_receive 从消息队列中获取OSAL消息，进行处理，例如按键消息等。然后，根据初始化事件的ID,处理初始化任务其中在初始化事件中开起一个系统级的定时器。最后是系统定时器的事件处理。