目录

1 前言

• 1.1 小型嵌入式系统中的多任务
  • 1.1.1 关于 FreeRTOS 内核
  • 1.1.2 价值主张
  • 1.1.3 关于术语的说明
  • 1.1.4 为什么要使用 RTOS？
  • 1.1.5 FreeRTOS 内核特性
  • 1.1.6 许可协议及 FreeRTOS、OpenRTOS 和 SafeRTOS 家族
• 1.2 附带的源文件和工程
  • 1.2.1 获取本书配套示例

2 FreeRTOS 内核分发包

• 2.1 简介
• 2.2 理解 FreeRTOS 分发包
  • 2.2.1 定义：FreeRTOS 移植
  • 2.2.2 构建 FreeRTOS
  • 2.2.3 FreeRTOSConfig.h
  • 2.2.4 官方分发包
  • 2.2.5 所有移植通用的 FreeRTOS 源文件
  • 2.2.6 针对特定移植的 FreeRTOS 源文件
  • 2.2.7 头文件包含路径
  • 2.2.8 头文件
• 2.3 演示应用
• 2.4 创建 FreeRTOS 工程
  • 2.4.1 适配提供的演示工程
  • 2.4.2 从零创建新工程
• 2.5 数据类型和编码风格指南
  • 2.5.1 数据类型
  • 2.5.2 变量命名
  • 2.5.3 函数命名
  • 2.5.4 格式化
  • 2.5.5 宏命名
  • 2.5.6 关于类型强制转换的说明

3 堆内存管理

• 3.1 简介
  • 3.1.1 前提条件
  • 3.1.2 范围
  • 3.1.3 在静态和动态内存分配之间切换
  • 3.1.4 使用动态内存分配
  • 3.1.5 动态内存分配的选项
• 3.2 示例内存分配方案
  • 3.2.1 Heap_1
  • 3.2.2 Heap_2
  • 3.2.3 Heap_3
  • 3.2.4 Heap_4
  • 3.2.5 Heap_5
  • 3.2.6 初始化 heap_5：vPortDefineHeapRegions() API 函数
• 3.3 堆相关的实用程序函数和宏
  • 3.3.1 定义堆起始地址
  • 3.3.2 xPortGetFreeHeapSize() API 函数
  • 3.3.3 xPortGetMinimumEverFreeHeapSize() API 函数
  • 3.3.4 vPortGetHeapStats() API 函数
  • 3.3.5 收集每个任务的堆使用统计信息
  • 3.3.6 内存分配失败钩子函数
  • 3.3.7 将任务堆栈放置在快速内存中
• 3.4 使用静态内存分配
  • 3.4.1 启用静态内存分配
  • 3.4.2 静态内部内核内存
  • 3.4.2.1 vApplicationGetTimerTaskMemory
  • 3.4.2.2 vApplicationGetIdleTaskMemory

4 任务管理

• 4.1 简介
  • 4.1.1 范围
• 4.2 任务函数
• 4.3 顶级任务状态
• 4.4 任务创建
  • 4.4.1 xTaskCreate() API 函数
• 4.5 任务优先级
  • 通用调度器
  • 架构优化调度器
• 4.6 时间测量和滴答中断
• 4.7 扩展“未运行”状态
  • 4.7.1 阻塞状态
  • 4.7.2 挂起状态
  • 4.7.3 就绪状态
  • 4.7.4 完成状态转换图
  • 4.7.5 vTaskDelayUntil() API 函数
• 4.8 空闲任务和空闲任务钩子
  • 4.8.1 空闲任务钩子函数
  • 4.8.2 空闲任务钩子函数的实现限制
• 4.9 改变任务优先级
  • 4.9.1 vTaskPrioritySet() API 函数
  • 4.9.2 uxTaskPriorityGet() API 函数
• 4.10 删除任务
  • 4.10.1 vTaskDelete() API 函数
• 4.11 线程本地存储和可重入性
  • 4.11.1 C 运行时线程本地存储实现
  • 4.11.2 自定义 C 运行时线程本地存储
  • 4.11.3 应用程序线程本地存储
• 4.12 调度算法
  • 4.12.1 任务状态和事件回顾
  • 4.12.2 选择调度算法
  • 4.12.3 带时间片的优先级抢占式调度
  • 4.12.4 不带时间片的优先级抢占式调度
  • 4.12.5 协作式调度

5 队列管理

• 5.1 简介
  • 5.1.1 范围
• 5.2 队列的特性
  • 5.2.1 数据存储
  • 5.2.2 多任务访问
  • 5.2.3 阻塞在队列读取上
  • 5.2.4 阻塞在队列写入上
  • 5.2.5 阻塞在多个队列上
  • 5.2.6 创建队列：静态分配和动态分配队列
• 5.3 使用队列
  • 5.3.1 xQueueCreate() API 函数
  • 5.3.2 xQueueSendToBack() 和 xQueueSendToFront() API 函数
  • 5.3.3 xQueueReceive() API 函数
  • 5.3.4 uxQueueMessagesWaiting() API 函数
• 5.4 从多个源接收数据
• 5.5 处理大数据或可变大小数据
  • 5.5.1 排队指针
  • 5.5.2 使用队列发送不同类型和长度的数据
• 5.6 从多个队列接收
  • 5.6.1 队列集
  • 5.6.2 xQueueCreateSet() API 函数
  • 5.6.3 xQueueAddToSet() API 函数
  • 5.6.4 xQueueSelectFromSet() API 函数
  • 5.6.5 更现实的队列集用例
• 5.7 使用队列创建邮箱
  • 5.7.1 xQueueOverwrite() API 函数
  • 5.7.2 xQueuePeek() API 函数

6 软件定时器管理

• 6.1 章节简介和范围
  • 6.1.1 范围
• 6.2 软件定时器回调函数
• 6.3 软件定时器的属性和状态
  • 6.3.1 软件定时器的周期
  • 6.3.2 单次和自动重载定时器
  • 6.3.3 软件定时器状态
• 6.4 软件定时器的上下文
  • 6.4.1 RTOS 守护（定时器服务）任务
  • 6.4.2 定时器命令队列
  • 6.4.3 守护任务调度
• 6.5 创建和启动软件定时器
  • 6.5.1 xTimerCreate() API 函数
  • 6.5.2 xTimerStart() API 函数
• 6.6 定时器 ID
  • 6.6.1 vTimerSetTimerID() API 函数
  • 6.6.2 pvTimerGetTimerID() API 函数
• 6.7 更改定时器的周期
  • 6.7.1 xTimerChangePeriod() API 函数
• 6.8 重置软件定时器
  • 6.8.1 xTimerReset() API 函数

7 中断管理

• 7.1 简介
  • 7.1.1 事件
  • 7.1.2 范围
• 7.2 在 ISR 中使用 FreeRTOS API
  • 7.2.1 中断安全 API
  • 7.2.2 使用单独的中断安全 API 的好处
  • 7.2.3 使用单独的中断安全 API 的缺点
  • 7.2.4 xHigherPriorityTaskWoken 参数
  • 7.2.5 portYIELD_FROM_ISR() 和 portEND_SWITCHING_ISR()宏
• 7.3 延迟中断处理
• 7.4 用于同步的二进制信号量
  • 7.4.1 xSemaphoreCreateBinary() API 函数
  • 7.4.2 xSemaphoreTake() API 函数
  • 7.4.3 xSemaphoreGiveFromISR() API 函数
  • 7.4.4 改进示例 7.1 中使用的任务的实现
• 7.5 计数信号量
  • 7.5.1 xSemaphoreCreateCounting() API 函数
• 7.6 将工作推迟到 RTOS 守护任务
  • 7.6.1 xTimerPendFunctionCallFromISR() API 函数
• 7.7 在中断服务例程中使用队列
  • 7.7.1 xQueueSendToFrontFromISR() 和 xQueueSendToBackFromISR() API 函数
  • 7.7.2 从 ISR 使用队列时的注意事项
• 7.8 中断嵌套
  • 7.8.1 针对 ARM Cortex-M 和 ARM GIC 用户的说明

8 资源管理

• 8.1 章节简介和范围
  • 8.1.1 互斥
  • 8.1.2 范围
• 8.2 关键段和挂起调度程序
  • 8.2.1 基本关键段
  • 8.2.2 挂起（或锁定）调度程序
  • 8.2.3 vTaskSuspendAll() API 函数
  • 8.2.4 xTaskResumeAll() API 函数
• 8.3 互斥量（和二进制信号量）
  • 8.3.1 xSemaphoreCreateMutex() API 函数
  • 8.3.2 优先级反转
  • 8.3.3 优先级继承
  • 8.3.4 死锁（或致命拥塞）
  • 8.3.5 递归互斥量
  • 8.3.6 互斥量和任务调度
• 8.4 守门人任务
  • 8.4.1 重写 vPrintString() 以使用守门人任务

9 事件组

• 9.1 章节简介与范围
  • 9.1.1 范围
• 9.2 事件组的特性
  • 9.2.1 事件组、事件标志和事件位
  • 9.2.2 有关 EventBits_t 数据类型的更多信息
  • 9.2.3 多任务访问
  • 9.2.4 使用事件组的实际示例
• 9.3 使用事件组进行事件管理
  • 9.3.1 xEventGroupCreate() API 函数
  • 9.3.2 xEventGroupSetBits() API 函数
  • 9.3.3 xEventGroupSetBitsFromISR() API 函数
  • 9.3.4 xEventGroupWaitBits() API 函数
  • 9.3.5 xEventGroupGetStaticBuffer() API 函数
• 9.4 使用事件组进行任务同步
  • 9.4.1 xEventGroupSync() API 函数

10 任务通知

• 10.1 简介
  • 10.1.1 通过中介对象通信
  • 10.1.2 任务通知——直接任务通信
  • 10.1.3 范围
• 10.2 任务通知的优缺点
  • 10.2.1 任务通知的性能优势
  • 10.2.2 RAM 占用优势
  • 10.2.3 任务通知的局限性
• 10.3 使用任务通知
  • 10.3.1 任务通知 API 选项
  • 10.3.1.1 完整的 API 函数列表
  • 10.3.2 xTaskNotifyGive() API 函数
  • 10.3.3 vTaskNotifyGiveFromISR() API 函数
  • 10.3.4 ulTaskNotifyTake() API 函数
  • 10.3.5 xTaskNotify() 和 xTaskNotifyFromISR() API 函数
  • 10.3.6 xTaskNotifyWait() API 函数
  • 10.3.7 任务通知在外设驱动中的应用：UART 示例
  • 10.3.8 任务通知在外设驱动中的应用：ADC 示例
  • 10.3.9 任务通知在应用程序中的直接使用

11 低功耗支持

• 11.1 节能简介
• 11.2 FreeRTOS 睡眠模式
• 11.3 启用内置无滴答空闲功能的方法
  • 11.3.1 portSUPPRESS_TICKS_AND_SLEEP() 宏
  • 11.3.2 vPortSuppressTicksAndSleep 函数
  • 11.3.3 eTaskConfirmSleepModeStatus 函数
  • 11.3.4 configPRE_SLEEP_PROCESSING 配置
  • 11.3.5 configPOST_SLEEP_PROCESSING 配置
• 11.4 Implementing portSUPPRESS_TICKS_AND_SLEEP() Macro
• 11.5 Idle Task Hook Function

12 开发者支持

• 12.1 简介
• 12.2 configASSERT()
  • 12.2.1 示例 configASSERT() 定义
• 12.3 Tracealyzer for FreeRTOS
• 12.4 调试相关的钩子（回调）函数
  • 12.4.1 内存分配失败钩子
  • 12.4.2 堆栈溢出钩子
• 12.5 查看运行时和任务状态信息
  • 12.5.1 任务运行时统计信息
  • 12.5.2 运行时统计时钟
  • 12.5.3 配置应用程序以收集运行时统计信息
  • 12.5.4 uxTaskGetSystemState() API 函数
  • 12.5.5 vTaskListTasks() 帮助函数
  • 12.5.6 vTaskGetRunTimeStatistics() 帮助函数
  • 12.5.7 生成和显示运行时统计信息的示例
• 12.6 跟踪钩子宏
  • 12.6.1 可用的跟踪钩子宏
  • 12.6.2 定义跟踪钩子宏
  • 12.6.3 FreeRTOS 感知调试器插件

13 故障排查

• 13.1 章节简介与范围
• 13.2 中断优先级
• 13.3 堆栈溢出
  • 13.3.1 The uxTaskGetStackHighWaterMark() API Function
  • 13.3.2 运行时堆栈检查 - 概述
  • 13.3.3 运行时堆栈检查 - 方法 1
  • 13.3.4 运行时堆栈检查 - 方法 2
  • 13.3.4 运行时堆栈检查 - 方法 3
• 13.4 对 printf() 和 sprintf() 的使用
  • 13.4.1 Printf-stdarg.c
• 13.5 其他常见错误来源
  • 13.5.1 症状：向演示添加简单任务导致演示崩溃
  • 13.5.2 症状：在中断中使用 API 函数导致应用崩溃
  • 13.5.3 症状：有时应用在中断服务例程中崩溃
  • 13.5.4 症状：调度器尝试启动第一个任务时崩溃
  • 13.5.5 症状：中断意外地保持禁用，或临界区未正确嵌套
  • 13.5.6 症状：应用程序在调度程序启动之前崩溃
  • 13.5.7 症状：在调度程序挂起或临界区内调用 API 函数导致应用崩溃
• 13.6 其他调试步骤

示例:

• Example 4.1 Creating tasks
• Example 4.2 Using the task parameter
• Example 4.3 Experimenting with priorities
• Example 4.4 Using the Blocked state to create a delay
• Example 4.5 Converting the example tasks to use vTaskDelayUntil()
• Example 4.6 Combining blocking and non-blocking tasks
• Example 4.7 Defining an idle task hook function
• Example 4.8 Deleting tasks
• Example 5.1 Blocking when receiving from a queue
• Example 5.2 Blocking when sending to a queue, and sending structures on a queue
• Example 5.3 Using a Queue Set
• Example 6.1 Creating one-shot and auto-reload timers
• Example 6.2 Using the callback function parameter and the software timer ID
• Example 6.3 Resetting a software timer
• Example 7.1 Using a binary semaphore to synchronize a task with an interrupt
• Example 7.2 Using a counting semaphore to synchronize a task with an interrupt
• Example 7.3 Centralized deferred interrupt processing
• Example 7.4 Sending and receiving on a queue from within an interrupt
• Example 8.1 Rewriting vPrintString() to use a semaphore
• Example 8.2 The alternative implementation for print task
• Example 9.1 Experimenting with event groups
• Example 9.2 Synchronizing tasks
• Example 10.1 Using a task notification in place of a semaphore, method 1
• Example 10.2 Using a task notification in place of a semaphore, method 2

插图:

• Figure 2.1 Top level directories within the FreeRTOS distribution
• Figure 2.2 Core FreeRTOS source files within the FreeRTOS directory tree
• Figure 2.3 Port specific source files within the FreeRTOS directory tree
• Figure 2.4 The demo directory hierarchy
• Figure 3.1 RAM being allocated from the heap_1 array each time a task is created
• Figure 3.2 RAM being allocated and freed from the heap_2 array as tasks are created and deleted
• Figure 3.3 RAM being allocated and freed from the heap_4 array
• Figure 3.4 Memory Map
• Figure 4.1 Top level task states and transitions
• Figure 4.2 The output produced when executing Example 4.1
• Figure 4.3 The actual execution pattern of the two Example 4.1 tasks
• Figure 4.4 The execution sequence expanded to show the tick interrupt executing
• Figure 4.5 Running both tasks at different priorities
• Figure 4.6 The execution pattern when one task has a higher priority than the...
• Figure 4.7 Full task state machine
• Figure 4.8 The output produced when Example 4.4 is executed
• Figure 4.9 The execution sequence when the tasks use vTaskDelay() in place of the null loop
• Figure 4.10 Bold lines indicate the state transitions performed by the tasks...
• Figure 4.11 The output produced when Example 4.6 is executed
• Figure 4.12 The execution pattern of Example 4.6
• Figure 4.13 The output produced when Example 4.7 is executed
• Figure 4.14 The sequence of task execution when running Example 4.8
• Figure 4.15 The output produced when Example 4.8 is executed
• Figure 4.16 The output produced when Example 4.9 is executed
• Figure 4.17 The execution sequence for Example 4.9
• Figure 4.18 Execution pattern highlighting task prioritization and preemption...
• Figure 4.19 Execution pattern highlighting task prioritization and time slicing...
• Figure 4.20 The execution pattern for the same scenario as shown in Figure 4.19...
• Figure 4.21 Execution pattern that demonstrates how tasks of equal priority can...
• Figure 4.22 Execution pattern demonstrating the behavior of the cooperative scheduler
• Figure 5.1 An example sequence of writes to, and reads from a queue
• Figure 5.2 The output produced when Example 5.1 is executed
• Figure 5.3 The sequence of execution produced by Example 5.1
• Figure 5.4 An example scenario where structures are sent on a queue
• Figure 5.5 The output produced by Example 5.2
• Figure 5.6 The sequence of execution produced by Example 5.2
• Figure 5.7 The output produced when Example 5.3 is executed
• Figure 6.1 The difference in behavior between one-shot and auto-reload software timers
• Figure 6.2 Auto-reload software timer states and transitions
• Figure 6.3 One-shot software timer states and transitions
• Figure 6.4 The timer command queue being used by a software timer API function to communicate with the RTOS daemon task
• Figure 6.5 The execution pattern when the priority of a task calling xTimerStart() is above the priority of the daemon task
• Figure 6.6 The execution pattern when the priority of a task calling xTimerStart() is below the priority of the daemon task
• Figure 6.7 The output produced when Example 6.1 is executed
• Figure 6.8 The output produced when Example 6.2 is executed
• Figure 6.9 Starting and resetting a software timer that has a period of 6 ticks
• Figure 6.10 The output produced when Example 6.3 is executed
• Figure 7.1 Completing interrupt processing in a high priority task
• Figure 7.2 Using a binary semaphore to implement deferred interrupt processing
• Figure 7.3 Using a binary semaphore to synchronize a task with an interrupt
• Figure 7.4 The output produced when Example 7.1 is executed
• Figure 7.5 The sequence of execution when Example 7.1 is executed
• Figure 7.6 The scenario when one interrupt occurs before the task has finished processing the first event
• Figure 7.7 The scenario when two interrupts occur before the task has finished processing the first event
• Figure 7.8 Using a counting semaphore to
• Figure 7.9 The output produced when Example 7.2 is executed
• Figure 7.10 The output produced when Example 7.3 is executed
• Figure 7.11 The sequence of execution when Example 7.3 is executed
• Figure 7.12 The output produced when Example 7.4 is executed
• Figure 7.13 The sequence of execution produced by Example 7.4
• Figure 7.14 Constants affecting interrupt nesting behavior
• Figure 7.15 How a priority of binary 101 is stored by a Cortex-M microcontroller that implements four priority bits
• Figure 8.1 Mutual exclusion implemented using a mutex
• Figure 8.2 The output produced when Example 8.1 is executed
• Figure 8.3 A possible sequence of execution for Example 8.1
• Figure 8.4 A worst case priority inversion scenario
• Figure 8.5 Priority inheritance minimizing the effect of priority inversion
• Figure 8.6 A possible sequence of execution when tasks that have the same priority use the same mutex
• Figure 8.7 A sequence of execution that could occur if two instances of the task shown by Listing 8.15 are created at the same priority
• Figure 8.8 The output produced when Example 8.2 is executed
• Figure 9.1 Event flag to bit number mapping in a variable of type EventBits_t
• Figure 9.2 An event group in which only bits 1, 4 and 7 are set, and all the other event flags are clear, making the event group
• Figure 9.3 The output produced when Example 9.1 is executed with xWaitForAllBits set to pdFALSE
• Figure 9.4 The output produced when Example 9.1 is executed with xWaitForAllBits set to pdTRUE
• Figure 9.5 The output produced when Example 9.2 is executed
• Figure 10.1 A communication object being used to send an event from one task to another
• Figure 10.2 A task notification used to send an event directly from one task to another
• Figure 10.3 The output produced when Example 7.1 is executed
• Figure 10.4 The sequence of execution when Example 10.1 is executed
• Figure 10.5 The output produced when Example 10.2 is executed
• Figure 10.6 The communication paths from the application tasks to the cloud server, and back again
• Figure 12.1 FreeRTOS+Trace includes more than 20 interconnected views
• Figure 12.2 FreeRTOS+Trace main trace view - one of more than 20 interconnected trace views
• Figure 12.3 FreeRTOS+Trace CPU load view - one of more than 20 interconnected trace views
• Figure 12.4 FreeRTOS+Trace response time view - one of more than 20 interconnected trace views
• Figure 12.5 FreeRTOS+Trace user event plot view - one of more than 20 interconnected trace views
• Figure 12.6 FreeRTOS+Trace kernel object history view - one of more than 20 interconnected trace views
• Figure 12.7 Example output generated by vTaskListTasks()
• Figure 12.8 Example output generated by vTaskGetRunTimeStatistics()

代码清单:

• Listing 2.1 The template for a new main() function
• Listing 3.1 The vPortDefineHeapRegions() API function prototype
• Listing 3.2 The HeapRegion_t structure
• Listing 3.3 An array of HeapRegion_t structures that together describe the 3 regions of RAM in their entirety
• Listing 3.4 An array of HeapRegion_t structures that describe all of RAM2, all of RAM3, but only part of RAM1
• Listing 3.5 Using GCC syntax to declare the array that will be used by heap_4, and place the array in a memory section named .my_heap
• Listing 3.6 Using IAR syntax to declare the array that will be used by heap_4, and place the array at the absolute address 0x20000000
• Listing 3.7 The xPortGetFreeHeapSize() API function prototype
• Listing 3.8 The xPortGetMinimumEverFreeHeapSize() API function prototype
• Listing 3.9 The vPortGetHeapStatus() API function prototype
• Listing 3.10 The HeapStatus_t() structure
• Listing 3.11 Collecting Per-task Heap Usage Statistics
• Listing 3.12 The malloc failed hook function name and prototype
• Listing 3.13 Mapping the pvPortMallocStack() and vPortFreeStack() macros to an application defined memory allcator
• Listing 3.14 Typical implementation of vApplicationGetTimerTaskMemory
• Listing 3.15 Typical implementation of vApplicationGetIdleTaskMemory
• Listing 4.1 The task function prototype
• Listing 4.2 The structure of a typical task function
• Listing 4.3 The xTaskCreate() API function prototype
• Listing 4.4 Implementation of the first task used in Example 4.1
• Listing 4.5 Implementation of the second task used in Example 4.1
• Listing 4.6 Starting the Example 4.1 tasks
• Listing 4.7 Creating a task from within another task after the scheduler has started
• Listing 4.8 The single task function used to create two tasks in Example 4.2
• Listing 4.9 The main() function for Example 2
• Listing 4.10 Using the pdMS_TO_TICKS() macro to convert 200 milliseconds...
• Listing 4.11. Creating two tasks at different priorities
• Listing 4.12 The vTaskDelay() API function prototype
• Listing 4.13 The source code for the example task after replacing the null loop delay with a call...
• Listing 4.14 vTaskDelayUntil() API function prototype
• Listing 4.15 The implementation of the example task using vTaskDelayUntil()
• Listing 4.16 The continuous processing task used in Example 4.6
• Listing 4.17 The periodic task used in Example 4.6
• Listing 4.18 The idle task hook function name and prototype
• Listing 4.19 A very simple Idle hook function
• Listing 4.20 The source code for the example task now prints out the ulIdleCycleCount value
• Listing 4.21 The vTaskPrioritySet() API function prototype
• Listing 4.22 The uxTaskPriorityGet() API function prototype
• Listing 4.23 The implementation of Task 1 in Example 4.8
• Listing 4.24 The implementation of Task 2 in Example 4.8
• Listing 4.25 The implementation of main() for Example 4.8
• Listing 4.26 The vTaskDelete() API function prototype
• Listing 4.27 The implementation of main() for Example 4.9
• Listing 4.28 The implementation of Task 1 for Example 4.9
• Listing 4.29 The implementation of Task 2 for Example 4.9
• Listing 4.30 Function prototypes of the Thread Local Storage Pointer API functions
• Listing 5.1 The xQueueCreate() API function prototype
• Listing 5.2 The xQueueSendToFront() API function prototype
• Listing 5.3 The xQueueSendToBack() API function prototype
• Listing 5.4 The xQueueReceive() API function prototype
• Listing 5.5 The uxQueueMessagesWaiting() API function prototype
• Listing 5.6 Implementation of the sending task used in Example 5.1
• Listing 5.7 Implementation of the receiver task for Example 5.1
• Listing 5.8 The implementation of main() in Example 5.1
• Listing 5.9 The definition of the structure that is to be passed on a queue, plus the declaration of two variables for use by the example
• Listing 5.10 The implementation of the sending task for Example 5.2
• Listing 5.11 The definition of the receiving task for Example 5.2
• Listing 5.12 The implementation of main() for Example 5.2
• Listing 5.13 Creating a queue that holds pointers
• Listing 5.14 Using a queue to send a pointer to a buffer
• Listing 5.15 Using a queue to receive a pointer to a buffer
• Listing 5.16 The structure used to send events to the TCP/IP stack task in FreeRTOS+TCP
• Listing 5.17 Pseudo code showing how an IPStackEvent_t structure is used to send data received from the network to the TCP/IP task
• Listing 5.18 Pseudo code showing how an IPStackEvent_t structure is used to send the handle of a socket that is accepting a connection to the TCP/IP task
• Listing 5.19 Pseudo code showing how an IPStackEvent_t structure is used to send a network down event to the TCP/IP task
• Listing 5.20 Pseudo code showing how an IPStackEvent_t structure is received and processed
• Listing 5.21 The xQueueCreateSet() API function prototype
• Listing 5.22 The xQueueAddToSet() API function prototype
• Listing 5.23 The xQueueSelectFromSet() API function prototype
• Listing 5.24 Implementation of main() for Example 5.3
• Listing 5.25 The sending tasks used in Example 5.3
• Listing 5.26 The receive task used in Example 5.3
• Listing 5.27 Using a queue set that contains queues and semaphores
• Listing 5.28 A queue being created for use as a mailbox
• Listing 5.29 The xQueueOverwrite() API function prototype
• Listing 5.30 Using the xQueueOverwrite() API function
• Listing 5.31 The xQueuePeek() API function prototype
• Listing 5.32 Using the xQueuePeek() API function
• Listing 6.1 The software timer callback function prototype
• Listing 6.2 The xTimerDelete() API function prototype
• Listing 6.3 The xTimerCreate() API function prototype
• Listing 6.4 The xTimerStart() API function prototype
• Listing 6.5 Creating and starting the timers used in Example 6.1
• Listing 6.6 The callback function used by the one-shot timer in Example 6.1
• Listing 6.7 The callback function used by the auto-reload timer in Example 6.1
• Listing 6.8 The vTimerSetTimerID() API function prototype
• Listing 6.9 The pvTimerGetTimerID() API function prototype
• Listing 6.10 Creating the timers used in Example 6.2
• Listing 6.11 The timer callback function used in Example 6.2
• Listing 6.12 The xTimerChangePeriod() API function prototype
• Listing 6.13 Using xTimerChangePeriod()
• Listing 6.14 The xTimerReset() API function prototype
• Listing 6.15 The callback function for the one-shot timer used in Example 6.3
• Listing 6.16 The task used to reset the software timer in Example 6.3
• Listing 7.1 The portEND_SWITCHING_ISR() macros
• Listing 7.2 The portYIELD_FROM_ISR() macros
• Listing 7.3 The xSemaphoreCreateBinary() API function prototype
• Listing 7.4 The xSemaphoreTake() API function prototype
• Listing 7.5 The xSemaphoreGiveFromISR() API function prototype
• Listing 7.6 Implementation of the task that periodically generates a software interrupt in Example 7.1
• Listing 7.7 The implementation of the task to which the interrupt processing is deferred (the task that...
• Listing 7.8 The ISR for the software interrupt used in Example 7.1
• Listing 7.9 The implementation of main() for Example 7.1
• Listing 7.10 The recommended structure of a deferred interrupt processing task, using a UART receive...
• Listing 7.11 The xSemaphoreCreateCounting() API function prototype
• Listing 7.12 The call to xSemaphoreCreateCounting() used to create the counting semaphore in Example 7.2
• Listing 7.13 The implementation of the interrupt service routine used by Example 7.2
• Listing 7.14 The xTimerPendFunctionCallFromISR() API function prototype
• Listing 7.15 The prototype to which a function passed in the xFunctionToPend parameter of xTimerPendFunctionCallFromISR()...
• Listing 7.16 The software interrupt handler used in Example 7.3
• Listing 7.17 The function that performs the processing necessitated by the interrupt in Example 7.3
• Listing 7.18 The implementation of main() for Example 7.3
• Listing 7.19 The xQueueSendToFrontFromISR() API function prototype
• Listing 7.20 The xQueueSendToBackFromISR() API function prototype
• Listing 7.21 The implementation of the task that writes to the queue in Example 7.4
• Listing 7.22 The implementation of the interrupt service routine used by Example 7.4
• Listing 7.23 The task that prints out the strings received from the interrupt service routine in Example 7.4
• Listing 7.24 The main() function for Example 7.4
• Listing 8.1 An example read, modify, write sequence
• Listing 8.2 An example of a reentrant function
• Listing 8.3 An example of a function that is not reentrant
• Listing 8.4 Using a critical section to guard access to a register
• Listing 8.5 A possible implementation of vPrintString()
• Listing 8.6 Using a critical section in an interrupt service routine
• Listing 8.7 The vTaskSuspendAll() API function prototype
• Listing 8.8 The xTaskResumeAll() API function prototype
• Listing 8.9 The implementation of vPrintString()
• Listing 8.10 The xSemaphoreCreateMutex() API function prototype
• Listing 8.11 The implementation of prvNewPrintString()
• Listing 8.12 The implementation of prvPrintTask() for Example 8.1
• Listing 8.13 The implementation of main() for Example 8.1
• Listing 8.14 Creating and using a recursive mutex
• Listing 8.15 A task that uses a mutex in a tight loop
• Listing 8.16 Ensuring tasks that use a mutex in a loop receive a more equal amount of processing time...
• Listing 8.17 The name and prototype for a tick hook function
• Listing 8.18 The gatekeeper task
• Listing 8.19 The print task implementation for Example 8.2
• Listing 8.20 The tick hook implementation
• Listing 8.21 The implementation of main() for Example 8.2
• Listing 9.1 The xEventGroupCreate() API function prototype
• Listing 9.2. The xEventGroupSetBits() API function prototype
• Listing 9.3 The xEventGroupSetBitsFromISR() API function prototype
• Listing 9.4 The xEventGroupWaitBits() API function prototype
• Listing 9.5 The xEventGroupGetStaticBuffer() API function prototype
• Listing 9.6 Event bit definitions used in Example 9.1
• Listing 9.7 The task that sets two bits in the event group in Example 9.1
• Listing 9.8 The ISR that sets bit 2 in the event group in Example 9.1
• Listing 9.9 The task that blocks to wait for event bits to become set in Example 9.1
• Listing 9.10 Creating the event group and tasks in Example 9.1
• Listing 9.11 Pseudo code for two tasks that synchronize with each other to ensure a shared TCP socket...
• Listing 9.12 The xEventGroupSync() API function prototype
• Listing 9.13 The implementation of the task used in Example 9.2
• Listing 9.14 The main() function used in Example 9.2
• Listing 10.1 The xTaskNotifyGive() API function prototype
• Listing 10.2 The vTaskNotifyGiveFromISR() API function prototype
• Listing 10.3 The ulTaskNotifyTake() API function prototype
• Listing 10.4 The implementation of the task to which the interrupt processing is deferred (the task that...
• Listing 10.5 The implementation of the interrupt service routine used in Example 10.1
• Listing 10.6 The implementation of the task to which the interrupt processing is deferred (the task...
• Listing 10.7 The implementation of the interrupt service routine used in Example 10.2
• Listing 10.8 Prototypes for the xTaskNotify() and xTaskNotifyFromISR() API functions
• Listing 10.9 The xTaskNotifyWait() API function prototype
• Listing 10.10 Pseudo code demonstrating how a binary semaphore can be used in a driver library transmit...
• Listing 10.11 Pseudo code demonstrating how a task notification can be used in a driver library transmit...
• Listing 10.12 Pseudo code demonstrating how a task notification can be used in a driver library receive...
• Listing 10.13 Pseudo code demonstrating how a task notification can be used to pass a value to a task
• Listing 10.14 The structure and data type sent on a queue to the server task
• Listing 10.15 The Implementation of the Cloud Read API Function
• Listing 10.16 The Server Task Processing a Read Request
• Listing 10.17 The Implementation of the Cloud Write API Function
• Listing 10.18 The Server Task Processing a Send Request
• Listing 11.1 The prototype for the portSUPPRESS_TICKS_AND_SLEEP macro
• Listing 11.2 The vPortSuppressTicksAndSleep API function prototype
• Listing 11.3 The eTaskConfirmSleepModeStatus API function prototype
• Listing 11.4 The prototype for the configPRE_SLEEP_PROCESSING macro
• Listing 11.5 The prototype for the configPOST_SLEEP_PROCESSING macro
• Listing 11.6 An example of a user defined implementation of portSUPPRESS_TICKS_AND_SLEEP()
• Listing 11.7 The vApplicationIdleHook API function prototype
• Listing 12.1 Using the standard C assert() macro to check pxMyPointer is not NULL
• Listing 12.2 A simple configASSERT() definition useful when executing under the control of a debugger
• Listing 12.3 A configASSERT() definition that records the source code line that failed an assertion
• Listing 12.4 The uxTaskGetSystemState() API function prototype
• Listing 12.5 The TaskStatus_t structure
• Listing 12.6 The vTaskListTasks() API function prototype
• Listing 12.7 The vTaskList() API function prototype
• Listing 12.8 The vTaskGetRunTimeStatistics() API function prototype
• Listing 12.9 The vTaskGetRunTimeStats() API function prototype
• Listing 12.10 16-bit timer overflow interrupt handler used to count timer overflows
• Listing 12.11 Macros added to FreeRTOSConfig.h to enable the collection of run-time statistics
• Listing 12.12 The task that prints out the collected run-time statistics
• Listing 13.1 The uxTaskGetStackHighWaterMark() API function prototype
• Listing 13.2 The uxTaskGetStackHighWaterMark2() API function prototype
• Listing 13.3 The stack overflow hook function prototype

表格:

• Table 1 FreeRTOS source files to include in the project
• Table 2 TickType_t data type and the configTICK_TYPE_WIDTH_IN_BITS configuration
• Table 3 Macro prefixes
• Table 4 Common macro definitions
• Table 5 The FreeRTOSConfig.h settings to configure the kernel scheduling algorithms
• Table 6 The Effect of the uxBitsToWaitFor and xWaitForAllBits Parameters