同步核心：

1、同步核心目标：任务1完成后再执行任务2（顺序执行

2、缺陷做法：用while循环等待任务1的标记为（g_calc_end）

        问题：忙等会持续抢占CPU，导致同优先级的任务1频繁被打断，执行时间翻倍

3、为什么缺陷：不是“占用时间”，是占用“CPU资源”

代码：

/* USER CODE BEGIN Header */
#include "driver_led.h"
#include "driver_lcd.h"
#include "driver_mpu6050.h"
#include "driver_timer.h"
#include "driver_ds18b20.h"
#include "driver_dht11.h"
#include "driver_active_buzzer.h"
#include "driver_passive_buzzer.h"
#include "driver_color_led.h"
#include "driver_ir_receiver.h"
#include "driver_ir_sender.h"
#include "driver_light_sensor.h"
#include "driver_ir_obstacle.h"
#include "driver_ultrasonic_sr04.h"
#include "driver_spiflash_w25q64.h"
#include "driver_rotary_encoder.h"
#include "driver_motor.h"
#include "driver_key.h"
#include "driver_uart.h"

/**
  ******************************************************************************
  * File Name          : freertos.c
  * Description        : Code for freertos applications
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "FreeRTOS.h"
#include "task.h"
#include "main.h"
#include "cmsis_os.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN Variables */
static StackType_t g_pucStackOfLightTask[128];//任务的栈
static StaticTask_t g_TCBofLightTask;//TCB
static TaskHandle_t xLightTaskHandle;//句柄

static StackType_t g_pucStackOfColorTask[128];
static StaticTask_t g_TCBofColorTask;
static TaskHandle_t xColorTaskHandle;

/* USER CODE END Variables */
/* Definitions for defaultTask */
osThreadId_t defaultTaskHandle;
const osThreadAttr_t defaultTask_attributes = {
  .name = "defaultTask",
  .stack_size = 128 * 4,
  .priority = (osPriority_t) osPriorityNormal,
};

/* Private function prototypes -----------------------------------------------*/
/* USER CODE BEGIN FunctionPrototypes */
struct TaskPrintInfo{
	uint8_t x;
	uint8_t y;
	char name[16];
};

static struct TaskPrintInfo g_Task1Info = {0,0,"Task1"};
static struct TaskPrintInfo g_Task2Info = {0,3,"Task2"};
static struct TaskPrintInfo g_Task3Info = {0,6,"Task3"};
static int g_LCDCanUse = 1;
static volatile int g_calc_end = 0;//这个地方没看懂
static uint64_t g_time = 0;
static uint32_t g_sum = 0;
//任务1：计算一个比较大的数值
void CalcTask(void *params)
{
	uint32_t i = 0;
	g_time = system_get_ns();
	for(i=0;i<10000000;i++)
	{
		g_sum+=i;
	}
	g_calc_end = 1;
	g_time = system_get_ns() - g_time;
	vTaskDelete(NULL);
	
}
//任务2：等待任务1计算完毕，打印数值和时间
void LcdPrintTask(void *params)
{
	int len;
	while(1)
	{
		
		LCD_PrintString(0,0,"Waiting");
		
		vTaskDelay(3000);
		
		while(g_calc_end == 0);//大部分时间在执行这个死循环
		
		/* 打印信息 */
		if(g_LCDCanUse)
		{
			g_LCDCanUse = 0;
			LCD_ClearLine(0,0);
			len = LCD_PrintString(0,0,"Sum:");
			len += LCD_PrintHex(len,0,g_sum,1);
			
			LCD_ClearLine(0,2);
			len = LCD_PrintString(0,2,"Time(ms):");
			len += LCD_PrintSignedVal(len,2,g_time/1000000);
			
			
			g_LCDCanUse = 1;
		}
		vTaskDelete(NULL);
		
	}
}



/* USER CODE END FunctionPrototypes */

void StartDefaultTask(void *argument);

void MX_FREERTOS_Init(void); /* (MISRA C 2004 rule 8.1) */

/**
  * @brief  FreeRTOS initialization
  * @param  None
  * @retval None
  */
void MX_FREERTOS_Init(void) {
  /* USER CODE BEGIN Init */
	TaskHandle_t xSoundTaskHandle;
	BaseType_t ret;
	LCD_Init();
	LCD_Clear();
  /* USER CODE END Init */

  /* USER CODE BEGIN RTOS_MUTEX */
  /* add mutexes, ... */
  /* USER CODE END RTOS_MUTEX */

  /* USER CODE BEGIN RTOS_SEMAPHORES */
  /* add semaphores, ... */
  /* USER CODE END RTOS_SEMAPHORES */

  /* USER CODE BEGIN RTOS_TIMERS */
  /* start timers, add new ones, ... */
  /* USER CODE END RTOS_TIMERS */

  /* USER CODE BEGIN RTOS_QUEUES */
  /* add queues, ... */
  /* USER CODE END RTOS_QUEUES */

  /* Create the thread(s) */
  /* creation of defaultTask */
  //defaultTaskHandle = osThreadNew(StartDefaultTask, NULL, &defaultTask_attributes);

  /* USER CODE BEGIN RTOS_THREADS */
  /* add threads, ... */
  /* 创建任务：声 */
  extern void PlayMusic(void *params);
  //ret = xTaskCreate(PlayMusic,"SoundTask",128,NULL,osPriorityNormal,&xSoundTaskHandle);
  
  /* 创建任务：光 */
  //xLightTaskHandle = xTaskCreateStatic(Led_Test,"LightTask",128,NULL,osPriorityNormal,g_pucStackOfLightTask,&g_TCBofLightTask);
  
  /* 创建任务：色 */
  //xColorTaskHandle = xTaskCreateStatic(ColorLED_Test,"ColorTask",128,NULL,osPriorityNormal,g_pucStackOfColorTask,&g_TCBofColorTask);
  
  /* 使用同一个函数创建不同的任务 */  
  xTaskCreate(CalcTask,"task1",128,NULL,osPriorityNormal,NULL);
  xTaskCreate(LcdPrintTask,"task2",128,&g_Task2Info,osPriorityNormal,NULL);
  //xTaskCreate(LcdPrintTask,"task3",128,&g_Task3Info,osPriorityNormal,NULL);
  /* USER CODE END RTOS_THREADS */

  /* USER CODE BEGIN RTOS_EVENTS */
  /* add events, ... */
  /* USER CODE END RTOS_EVENTS */

}

/* USER CODE BEGIN Header_StartDefaultTask */

/**
  * @brief  Function implementing the defaultTask thread.
  * @param  argument: Not used
  * @retval None
  */
/* USER CODE END Header_StartDefaultTask */
void StartDefaultTask(void *argument)
{
  /* USER CODE BEGIN StartDefaultTask */
  /* Infinite loop */
  LCD_Init();
  LCD_Clear();
  
  for(;;)
  {
    //Led_Test();
    //LCD_Test();
	//MPU6050_Test(); 
	//DS18B20_Test();
	//DHT11_Test();
	//ActiveBuzzer_Test();
	//PassiveBuzzer_Test();
	//ColorLED_Test();
	IRReceiver_Test();//影
	//IRSender_Test();
	//LightSensor_Test();
	//IRObstacle_Test();
	//SR04_Test();
	//W25Q64_Test();
	//RotaryEncoder_Test();
	//Motor_Test();
	//Key_Test();
	//UART_Test();
  }
  /* USER CODE END StartDefaultTask */
}

/* Private application code --------------------------------------------------*/
/* USER CODE BEGIN Application */

/* USER CODE END Application */

互斥

# 互斥操作漏洞

1. 基础问题：多任务同时判断标志位 → 都占用资源，互斥失效

2. 原子操作问题：++/--是读-改-写三步骤 → 仍有间隙，抢占问题未根治

如何不被打断：1.关中断2.freertos互斥锁（A使用时，B阻塞）