[detailed steps of FreeRTOS shift value for the first time]

FreeRTOS Shift value

---

---

Tips ： The following is the main body of this article , The following cases can be used for reference

One 、 What is? FreeRTOS？

FreeRTOS Name , It can be divided into two parts :Free and RTOS,Free It's free 、 The freedom of the 、 Unconstrained meaning ,RTOS The full name is Real Time Operating System, The Chinese name is the real-time operating system . It can be seen that FreeROTS It's a free RTOS Class system . Pay attention here ,RTOS It doesn't mean a certain system , It's a system . such as UCOS,FreeRTOS,RTX,RT-Thread Wait, these are all RTOS Class operating system .

Two 、FreeRTOS Characteristics

FreeRTOS It's a croppable small RTOS System , Its features include ：
● FreeRTOS The kernel supports preemptive , Cooperative and time slice scheduling .
● SafeRTOS Derived from FreeRTOS,SafeRTOS In terms of code integrity FreeRTOS better .
● A method for low power consumption is provided Tickless Pattern .
● System components can be created dynamically or statically RAM, For example, tasks 、 Message queue 、 Semaphore 、 Software timer, etc .
● It's already surpassing 30 The architecture is transplanted on the chip . ● FreeRTOS-MPU Support Corex-M In the series MPU unit , Such as STM32F103.
● FreeRTOS The system is simple 、 small 、 Easy to use , Usually, the kernel occupies 4k-9k Byte space .
● High portability , Code main C Language writing .
● Support real-time tasks and collaborative processes (co-routines It is also called cooperative 、 Collaborative process , This tutorial has become a collaborative process ).
● Tasks and tasks 、 Task notifications can be used between tasks and interrupts 、 Message queue 、 Binary semaphore 、 Numeric letter Number quantity 、 Recursive mutex semaphores and mutex semaphores communicate and synchronize .
● Innovative event group ( Or event flags ).
● Mutually exclusive semaphores with priority inheritance .
● Efficient software timer .
● Powerful tracking execution function .
● Stack overflow detection function .
● There is no limit to the number of tasks .
● There is no limit to task priority .

Get to the point FreeRTOS Shift value

3、 ... and 、FreeRTOS Shift value

 The following is based on the firmware library template FreeRTOS Shift value 

3.1、 add to FreeRTOS Source code

First, we create the following folders in the firmware library template

establish FreeRTOS Folder, you can put FreeRTOS Add the source code to this folder （ As shown in the figure below ）HARDWARE It is used to store the peripheral code we use later SYSTEM It is used to store system files, which will be introduced below

portable Folder , We just need to stay keil、MemMang and RVDS These three folders , Others can be deleted , After completion, as shown in the figure

3.2、 Open firmware library project Add files to the group for the project files under

Add the following groups c The files are imported into the corresponding folders

add to c file , Click the button below to add a shortcut

3.3、 Add file path

Click on the magic wand choice c/c++ Corresponding c Add the path of the header file

 That's it FreeRTOS Simple value shifting and environment configuration 

Four 、FreeRTOS First experiment

 Next we will move the value of good FreeRTOS Perform simple multitasking procedures  
 Used in the project  usart sys delay  Relevant documents are put in SYSTEM In folder   I will put the complete file below .

/*---------------------------------------------------------------------- * first FreeRTOS experiment  *Date:2022-2-12 *Author: Xiao Yin  *---------------------------------------------------------------------*/

#include "sys.h"
#include "delay.h"
#include "usart.h"
#include "led.h"
#include "FreeRTOS.h"
#include "task.h"


// Task priority 
#define START_TASK_PRIO 1
// Task stack size  
#define START_STK_SIZE 128 
// Task to handle 
TaskHandle_t StartTask_Handler;
// Task function 
void start_task(void *pvParameters);

// Task priority 
#define LED0_TASK_PRIO 2
// Task stack size  
#define LED0_STK_SIZE 50 
// Task to handle 
TaskHandle_t LED0Task_Handler;
// Task function 
void led0_task(void *pvParameters);

// Task priority 
#define LED1_TASK_PRIO 3
// Task stack size  
#define LED1_STK_SIZE 50 
// Task to handle 
TaskHandle_t LED1Task_Handler;
// Task function 
void led1_task(void *pvParameters);

int main(void)
{
    
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);// Set system interrupt priority group 4 
	delay_init();	    				// Delay function initialization  
	uart_init(115200);					// Initialize serial port 
	LED_Init();		  					// initialization LED
	 
	// Create start task 
    xTaskCreate((TaskFunction_t )start_task,            // Task function 
                (const char*    )"start_task",          // The name of the task 
                (uint16_t       )START_STK_SIZE,        // Task stack size 
                (void*          )NULL,                  // Parameters passed to the task function 
                (UBaseType_t    )START_TASK_PRIO,       // Task priority 
                (TaskHandle_t*  )&StartTask_Handler);   // Task to handle  
    vTaskStartScheduler();          // Turn on task scheduling 
}

// Start task task function 
void start_task(void *pvParameters)
{
    
    taskENTER_CRITICAL();           // Enter the critical area 
    // establish LED0 Mission 
    xTaskCreate((TaskFunction_t )led0_task,     	
                (const char*    )"led0_task",   	
                (uint16_t       )LED0_STK_SIZE, 
                (void*          )NULL,				
                (UBaseType_t    )LED0_TASK_PRIO,	
                (TaskHandle_t*  )&LED0Task_Handler);   
    // establish LED1 Mission 
    xTaskCreate((TaskFunction_t )led1_task,     
                (const char*    )"led1_task",   
                (uint16_t       )LED1_STK_SIZE, 
                (void*          )NULL,
                (UBaseType_t    )LED1_TASK_PRIO,
                (TaskHandle_t*  )&LED1Task_Handler);         
    vTaskDelete(StartTask_Handler); // Delete start task 
    taskEXIT_CRITICAL();            // Exit critical region 
}

//LED0 Task function  
void led0_task(void *pvParameters)
{
    
    while(1)
    {
    
        LED0=~LED0;
        vTaskDelay(500);
			  printf("led1 is running\r\n");
    }
}   

//LED1 Task function 
void led1_task(void *pvParameters)
{
    
    while(1)
    {
    
        LED1=0;
        vTaskDelay(200);
        LED1=1;
        vTaskDelay(800);
				printf("led2 is running\r\n");
    }
}

The specific relevant parameters in the code are not introduced Basic people can go B Stand and learn

 because stm32f103c8t6 Only one onboard LED  We print through serial port 

Be careful

 The above multi task creation is created in a dynamic form   It is a little different from static creation 
 During dynamic creation, we will define the following macro   by 0  When using static creation, it is 1

configSUPPORT_STATIC_ALLOCATION    1  Set to 1  If you use the dynamic creation method, the following error will appear. Just modify it accordingly 

---

 Links to related materials 

link ：https://pan.baidu.com/s/1EXxSt6QEd1lCaXnlDryv-g
Extraction code ：8ac6
– From Baidu network disk super member V4 The share of