第七讲：嵌入式实时操作系统FreeRTOS

21天学嵌入式开发第七讲：嵌入式实时操作系统FreeRTOS

课程安排嵌入式实时操作系统FreeRTOS简介

嵌入式操作系统基本概念

FreeRTOS的API模块嵌入式实时操作系统FreeRTOS简介FreeRTOS是一个可移植的、开源的小型实时内核。FreeRTOS支持的处理器架构有如下几种：

ARM7,ARM9,Cortex-M3AtmelAVR32AtmelAVRMicrochipPICMicroPIC18,PIC24,dsPICandPIC32MSP430ColdFireHCS12NEC16and32bitprocessorsXilinxVirtex4FPGA嵌入式实时操作系统FreeRTOS简介FreeRTOS的主要功能：优先级调度、相同优先级任务的轮转调度，同时可设成可剥夺内核或不可剥夺内核任务可选择是否共享堆栈，并且没有任务数限制消息队列，二值信号量，计数信号量，递归互斥体时间管理内存管理

嵌入式操作系统基本概念

多任务

调度

上下文切换

实时应用和调度

FreeRTOS的API模块定制

FreeRTOSConfig.h

#ifndefFREERTOS_CONFIG_H#defineFREERTOS_CONFIG_H#include"something.h"#defineconfigUSE_PREEMPTION1#defineconfigUSE_IDLE_HOOK0#defineconfigUSE_TICK_HOOK0#defineconfigCPU_CLOCK_HZ58982400#defineconfigTICK_RATE_HZ250#defineconfigMAX_PRIORITIES5#defineconfigMINIMAL_STACK_SIZE128#defineconfigTOTAL_HEAP_SIZE10240#defineconfigMAX_TASK_NAME_LEN16#defineconfigUSE_TRACE_FACILITY0#defineconfigUSE_16_BIT_TICKS0#defineconfigIDLE_SHOULD_YIELD1#defineconfigUSE_MUTEXES0#defineconfigUSE_RECURSIVE_MUTEXES0#defineconfigUSE_COUNTING_SEMAPHORES0#defineconfigUSE_ALTERNATIVE_API0#defineconfigCHECK_FOR_STACK_OVERFLOW0#defineconfigQUEUE_REGISTRY_SIZE10#defineINCLUDE_vTaskPrioritySet1#defineINCLUDE_uxTaskPriorityGet1#defineINCLUDE_vTaskDelete1#defineINCLUDE_vTaskCleanUpResources0#defineINCLUDE_vTaskSuspend1#defineINCLUDE_vResumeFromISR1#defineINCLUDE_vTaskDelayUntil1#defineINCLUDE_vTaskDelay1#defineINCLUDE_xTaskGetSchedulerState1#defineINCLUDE_xTaskGetCurrentTaskHandle1#defineINCLUDE_uxTaskGetStackHighWaterMark0#defineconfigUSE_CO_ROUTINES0#defineconfigMAX_CO_ROUTINE_PRIORITIES1#defineconfigKERNEL_INTERRUPT_PRIORITY [dependentofprocessor]#defineconfigMAX_SYSCALL_INTERRUPT_PRIORITY [dependentonprocessor andapplication]#endif/*FREERTOS_CONFIG_H*/FreeRTOS的API模块任务创建和删除

portBASE_TYPExTaskCreate(pdTASK_CODEpvTaskCode,constportCHAR*constpcName,unsignedportSHORTusStackDepth,void*pvParameters,unsignedportBASE_TYPEuxPriority,xTaskHandle*pvCreatedTask);FreeRTOS的API模块任务控制vTaskDelay

vTaskDelayUntil

uxTaskPriorityGet

vTaskPrioritySet

vTaskSuspend

vTaskResume

vTaskResumeFromISR

vTaskSetApplicationTag

vxTaskCal