FreeRTOS 基础简介

女爷i 2022-06-08 05:29 306阅读 0赞

**为什么选择FreeRTOS**  
UCOS资料多，尤其是中文资料。FreeRTOS资料少，而且大多数是英文的。原因如下：

> 1.FreeRTOS免费！UCOS收费。这是主要原因  
> 2.很多半导体厂商，采用FreeRTOS作为其操作系统  
> 3.FreeRTOS文件数量少

**下载地址**  
[http://www.freertos.org/][http_www.freertos.org]

**目录结构**

# ls -l
    total 28
    drwx------ 5 pi pi 4096 Sep 16 04:17 FreeRTOS
    drwx------ 4 pi pi 4096 Sep 16 04:18 FreeRTOS-Plus
    -rwx------ 1 pi pi 141 Jan 16 2015 New - Direct to Task Notifications.url -rwx------ 1 pi pi 155 Dec 21 2014 New - FreeRTOS+TCP.url -rwx------ 1 pi pi 144 Sep 17 2013 Quick_Start_Guide.url -rwx------ 1 pi pi 1468 Sep 17 2013 readme.txt -rwx------ 1 pi pi 129 Feb 19 2016 Upgrading-to-FreeRTOS-9.url

> FreeRTOS-Plus：包含FreeRTOS+组件和演示例程  
> FreeRTOS：包含FreeRTOS实时内核源文件和演示例程

# ls -l FreeRTOS
    total 28
    drwx------ 166 pi pi 12288 Sep 16 04:17 Demo
    drwx------ 2 pi pi 4096 Sep 16 04:17 License
    -rwx------ 1 pi pi 124 Oct 30 2014 links_to_doc_pages_for_the_demo_projects.url
    -rwx------ 1 pi pi 912 Sep 17 2013 readme.txt
    drwx------ 4 pi pi 4096 Sep 16 04:17 Source

> Demo：演示例程  
> License：许可信息  
> Source：实时内核源文件

# ls -l FreeRTOS/Source/
    total 352
    -rwx------ 1 pi pi 15771 May 20 2016 croutine.c -rwx------ 1 pi pi 26251 May 20 2016 event_groups.c drwx------  2 pi pi   4096 Sep 16 04:17 include
    -rwx------ 1 pi pi 10993 May 20 2016 list.c drwx------ 22 pi pi   4096 Sep 16 04:17 portable
    -rwx------ 1 pi pi 83729 May 20 2016 queue.c -rwx------ 1 pi pi 822 Sep 17 2013 readme.txt -rwx------ 1 pi pi 157816 May 20 2016 tasks.c -rwx------ 1 pi pi 41115 May 20 2016 timers.c

> tasks.c、queue.c、list.c：核心文件  
> timers.c、event\_groups.c、croutine.c：可选文件  
> include：内核代码头文件  
> portable：处理器特定代码

# ls FreeRTOS/Source/portable/ -l
    total 84
    drwx------ 3 pi pi 4096 Sep 16 04:17 BCC
    drwx------ 5 pi pi 4096 Sep 16 04:17 CCS
    drwx------ 5 pi pi 4096 Sep 16 04:17 CodeWarrior
    drwx------ 2 pi pi 4096 Sep 16 04:17 Common
    drwx------ 37 pi pi 4096 Sep 16 04:17 GCC
    drwx------ 25 pi pi 4096 Sep 16 04:17 IAR
    drwx------ 2 pi pi 4096 Sep 16 04:17 Keil
    drwx------ 2 pi pi 4096 Sep 16 04:17 MemMang
    drwx------ 3 pi pi 4096 Sep 16 04:17 MikroC
    drwx------ 7 pi pi 4096 Sep 16 04:17 MPLAB
    drwx------ 2 pi pi 4096 Sep 16 04:17 MSVC-MingW
    drwx------ 3 pi pi 4096 Sep 16 04:17 oWatcom
    drwx------ 3 pi pi 4096 Sep 16 04:17 Paradigm
    -rwx------ 1 pi pi 866 Feb 11 2016 readme.txt
    drwx------ 7 pi pi 4096 Sep 16 04:17 Renesas
    drwx------ 4 pi pi 4096 Sep 16 04:17 Rowley
    drwx------ 9 pi pi 4096 Sep 16 04:17 RVDS
    drwx------ 3 pi pi 4096 Sep 16 04:17 SDCC
    drwx------ 4 pi pi 4096 Sep 16 04:17 Softune
    drwx------ 3 pi pi 4096 Sep 16 04:17 Tasking
    drwx------ 3 pi pi 4096 Sep 16 04:17 WizC

> Keil、RVDS：使用MDK环境编译所需要的文件  
> MemMang：内存管理，堆栈实现

# ls -l FreeRTOS/Demo/Common/
    total 24
    drwx------ 5 pi pi 4096 Sep 16 04:04 drivers
    drwx------ 9 pi pi 4096 Sep 16 04:05 ethernet
    drwx------ 2 pi pi 4096 Sep 16 04:06 Full
    drwx------ 2 pi pi 4096 Sep 16 04:06 include
    drwx------ 2 pi pi 4096 Sep 16 04:06 Minimal
    -rwx------ 1 pi pi 737 Mar 29 2016 ReadMe.txt

> Common：演示例程

**测试Demo**  
替换原有main函数，测试LED闪烁

int main( void )
    {
        volatile unsigned long ul; /* volatile so it is not optimized away. */
    
        prvSetupHardware(); //时钟设置
        vParTestInitialise(); //gpio初始化
    
        /* Toggle the LEDs repeatedly. */
        for( ;; )
        {
            /* We don't want to use the RTOS features yet, so just use a very crude delay mechanism instead. */
            for( ul = 0; ul < 0xfffff; ul++ )
            {
            }
    
            /* Toggle the first four LEDs (on the assumption there are at least 4 fitted. */
            vParTestToggleLED( 0 );
            vParTestToggleLED( 1 );
            vParTestToggleLED( 2 );
            vParTestToggleLED( 3 );
        }
    
        return 0;
    }

**RTOS调度器**  
LED不同频率的闪烁

int main( void )
    {
       /* Setup the microcontroller hardware for the demo. */
       prvSetupHardware();
    
       vStartLEDFlashTasks( mainFLASH_TASK_PRIORITY );
    
       /* All other functions that create tasks are commented out. vCreatePollQTasks(); vCreateComTestTasks(); Etc. xTaskCreate( vCheckTask, "check", STACK_SIZE, NULL, TASK_PRIORITY, NULL ); */
    
       /* Start the RTOS scheduler. */
       vTaskStartScheduler();
    
       /* Should never get here! */
       return 0;
    }

`参考：`[http://www.freertos.org/porting-a-freertos-demo-to-different-hardware.html][http_www.freertos.org_porting-a-freertos-demo-to-different-hardware.html]

[http_www.freertos.org]: http://www.freertos.org/
[http_www.freertos.org_porting-a-freertos-demo-to-different-hardware.html]: http://www.freertos.org/porting-a-freertos-demo-to-different-hardware.html