STM32CUBEIDE FreeRTOS操作教程（五）：mutex互斥信号量
STM32CUBE开发环境集成了STM32 HAL库进行FreeRTOS配置和开发的组件，不需要用户自己进行FreeRTOS的移植。这里介绍最简化的用户操作类应用教程。以STM32F401RCT6开发板为例，只用到USB，USART1极少的接口，体现FreeRTOS的各种操作过程。
操作教程（五）配置FreeRTOS及相关环境，实现LED闪灯功能及基于mutex互斥信号量的USB虚拟串口双任务打印输出。两个任务轮流获取和释放互斥信号量，在得到信号量时向外打印输出。
FreeRTOS的教程较多，推荐参考正点原子所出的《STM32F407 FreeRTOS开发手册》了解相关知识。
STM32CUBEIDE工程配置
选择TIM1(也可以是其它TIM)作为FreeRTOS操作系统占用的时钟源：
配置时钟树包括USB的48MHz时钟：
配置PC13为低电平点灯的管脚：
配置USB串口:
配置UART1串口（但本例中不用到UART1):
FreeRTOS配置
保存并生成初始工程代码：
在生成代码的这个部分可以看到FreeRTOS代码部分：
任务实现
基于前述的配置，main.c代码里会加载Free-RTOS的配置，并启动几个任务的调度，当然，此时的任务都是什么也不干。实现LED闪灯，就在LED闪灯任务里加入代码即可：
void StartTask_TASK_LED_FLASH(void *argument)
{/* USER CODE BEGIN StartTask_TASK_LED_FLASH *//* Infinite loop */for(;;){osDelay(1000);HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);}/* USER CODE END StartTask_TASK_LED_FLASH */
}
也就实现了LED闪灯功能，其中osDelay(1000);实现1秒时间的操作系统调度延时，也就是1秒执行一次LED灯的亮灭。osDelay(1）；是最小的调度延时，为1毫秒。要实现更小的延时，则可以用微秒延时函数实现，参考《STM32 HAL us delay（微秒延时）的指令延时实现方式及优化》
main.c文件里两个任务分别通过获取互斥信号量权柄，再发送信息：
void StartTask_TASK_USB_VCOM_H(void *argument)
{/* USER CODE BEGIN StartTask_TASK_USB_VCOM_H */BaseType_t err_stu = pdFALSE;/* Infinite loop */for(;;){osDelay(8);err_stu = xSemaphoreTake(USB_VCOM_Mutex01Handle, USB_VCOM_xBlockTime);if(err_stu==pdTRUE){if(USB_CONN_STATUS()){usbprintstring("Task 1 Outputting\r\n");}xSemaphoreGive(USB_VCOM_Mutex01Handle);}}/* USER CODE END StartTask_TASK_USB_VCOM_H */
}void StartTask_TASK_USB_VCOM_L(void *argument)
{/* USER CODE BEGIN StartTask_TASK_USB_VCOM_L */BaseType_t err_stu = pdFALSE;/* Infinite loop */for(;;){osDelay(5);err_stu = xSemaphoreTake(USB_VCOM_Mutex01Handle, USB_VCOM_xBlockTime);if(err_stu==pdTRUE){if(USB_CONN_STATUS()){usbprintstring("Task 2 Outputting\r\n");}osDelay(10);xSemaphoreGive(USB_VCOM_Mutex01Handle);}}/* USER CODE END StartTask_TASK_USB_VCOM_L */
}
完整的main.c代码：
/* USER CODE BEGIN Header */
/********************************************************************************* @file : main.c* @brief : Main program body******************************************************************************* @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.********************************************************************************/
//Example 5: LED flash + Mutex
//Written by Pegasus Yu
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "cmsis_os.h"
#include "usb_device.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "semphr.h"
/* USER CODE END Includes *//* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
__IO float usDelayBase = 7.63238716; //For STM32F401RCT6 working in 84MHz main clockvoid PY_Delay_us_t(uint32_t Delay)
{__IO uint32_t delayReg;__IO uint32_t usNum = (uint32_t)(Delay*usDelayBase);delayReg = 0;while(delayReg!=usNum) delayReg++;
}
/* 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 ---------------------------------------------------------*/
UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_rx;/* Definitions for defaultTask */
osThreadId_t defaultTaskHandle;
const osThreadAttr_t defaultTask_attributes = {.name = "defaultTask",.stack_size = 128 * 4,.priority = (osPriority_t) osPriorityNormal,
};
/* Definitions for TASK_LED_FLASH */
osThreadId_t TASK_LED_FLASHHandle;
const osThreadAttr_t TASK_LED_FLASH_attributes = {.name = "TASK_LED_FLASH",.stack_size = 128 * 4,.priority = (osPriority_t) osPriorityLow,
};
/* Definitions for TASK_UART1 */
osThreadId_t TASK_UART1Handle;
const osThreadAttr_t TASK_UART1_attributes = {.name = "TASK_UART1",.stack_size = 128 * 4,.priority = (osPriority_t) osPriorityLow,
};
/* Definitions for TASK_USB_VCOM_H */
osThreadId_t TASK_USB_VCOM_HHandle;
const osThreadAttr_t TASK_USB_VCOM_H_attributes = {.name = "TASK_USB_VCOM_H",.stack_size = 128 * 4,.priority = (osPriority_t) osPriorityHigh,
};
/* Definitions for TASK_USB_VCOM_L */
osThreadId_t TASK_USB_VCOM_LHandle;
const osThreadAttr_t TASK_USB_VCOM_L_attributes = {.name = "TASK_USB_VCOM_L",.stack_size = 128 * 4,.priority = (osPriority_t) osPriorityLow,
};
/* Definitions for USB_VCOM_Mutex01 */
osMutexId_t USB_VCOM_Mutex01Handle;
const osMutexAttr_t USB_VCOM_Mutex01_attributes = {.name = "USB_VCOM_Mutex01"
};
/* USER CODE BEGIN PV *//* USER CODE END PV *//* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART1_UART_Init(void);
void StartDefaultTask(void *argument);
void StartTask_TASK_LED_FLASH(void *argument);
void StartTask_TASK_UART1(void *argument);
void StartTask_TASK_USB_VCOM_H(void *argument);
void StartTask_TASK_USB_VCOM_L(void *argument);/* USER CODE BEGIN PFP *//* USER CODE END PFP *//* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
uint8_t USB_CONN_STATUS(void);
uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len);
void usbprintstring(char * data)
{if(CDC_Transmit_FS((uint8_t *)data, strlen(data))==USBD_BUSY){PY_Delay_us_t(1000000);CDC_Transmit_FS((uint8_t *)data, strlen(data));}
}void usbprintarray(uint8_t * data, uint16_t len)
{if(CDC_Transmit_FS(data, len)==USBD_BUSY){PY_Delay_us_t(1000000);CDC_Transmit_FS(data, len);}
}BaseType_t USB_VCOM_pxHigherPriorityTaskWaken;
TickType_t USB_VCOM_xBlockTime = 0;
/* USER CODE END 0 *//*** @brief The application entry point.* @retval int*/
int main(void)
{/* USER CODE BEGIN 1 *//* USER CODE END 1 *//* MCU Configuration--------------------------------------------------------*//* Reset of all peripherals, Initializes the Flash interface and the Systick. */HAL_Init();/* USER CODE BEGIN Init *//* USER CODE END Init *//* Configure the system clock */SystemClock_Config();/* USER CODE BEGIN SysInit *//* USER CODE END SysInit *//* Initialize all configured peripherals */MX_GPIO_Init();MX_DMA_Init();MX_USART1_UART_Init();/* USER CODE BEGIN 2 *//* USER CODE END 2 *//* Init scheduler */osKernelInitialize();/* Create the mutex(es) *//* creation of USB_VCOM_Mutex01 */USB_VCOM_Mutex01Handle = osMutexNew(&USB_VCOM_Mutex01_attributes);/* 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);/* creation of TASK_LED_FLASH */TASK_LED_FLASHHandle = osThreadNew(StartTask_TASK_LED_FLASH, NULL, &TASK_LED_FLASH_attributes);/* creation of TASK_UART1 */TASK_UART1Handle = osThreadNew(StartTask_TASK_UART1, NULL, &TASK_UART1_attributes);/* creation of TASK_USB_VCOM_H */TASK_USB_VCOM_HHandle = osThreadNew(StartTask_TASK_USB_VCOM_H, NULL, &TASK_USB_VCOM_H_attributes);/* creation of TASK_USB_VCOM_L */TASK_USB_VCOM_LHandle = osThreadNew(StartTask_TASK_USB_VCOM_L, NULL, &TASK_USB_VCOM_L_attributes);/* USER CODE BEGIN RTOS_THREADS *//* add threads, ... *//* USER CODE END RTOS_THREADS *//* USER CODE BEGIN RTOS_EVENTS *//* add events, ... *//* USER CODE END RTOS_EVENTS *//* Start scheduler */osKernelStart();/* We should never get here as control is now taken by the scheduler *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Configure the main internal regulator output voltage*/__HAL_RCC_PWR_CLK_ENABLE();__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLM = 25;RCC_OscInitStruct.PLL.PLLN = 336;RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;RCC_OscInitStruct.PLL.PLLQ = 7;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK){Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks*/RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK){Error_Handler();}
}/*** @brief USART1 Initialization Function* @param None* @retval None*/
static void MX_USART1_UART_Init(void)
{/* USER CODE BEGIN USART1_Init 0 *//* USER CODE END USART1_Init 0 *//* USER CODE BEGIN USART1_Init 1 *//* USER CODE END USART1_Init 1 */huart1.Instance = USART1;huart1.Init.BaudRate = 115200;huart1.Init.WordLength = UART_WORDLENGTH_8B;huart1.Init.StopBits = UART_STOPBITS_1;huart1.Init.Parity = UART_PARITY_NONE;huart1.Init.Mode = UART_MODE_TX_RX;huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart1.Init.OverSampling = UART_OVERSAMPLING_16;if (HAL_UART_Init(&huart1) != HAL_OK){Error_Handler();}/* USER CODE BEGIN USART1_Init 2 *//* USER CODE END USART1_Init 2 */}/*** Enable DMA controller clock*/
static void MX_DMA_Init(void)
{/* DMA controller clock enable */__HAL_RCC_DMA2_CLK_ENABLE();/* DMA interrupt init *//* DMA2_Stream2_IRQn interrupt configuration */HAL_NVIC_SetPriority(DMA2_Stream2_IRQn, 5, 0);HAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);}/*** @brief GPIO Initialization Function* @param None* @retval None*/
static void MX_GPIO_Init(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 *//* GPIO Ports Clock Enable */__HAL_RCC_GPIOC_CLK_ENABLE();__HAL_RCC_GPIOH_CLK_ENABLE();__HAL_RCC_GPIOA_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(LED_GPIO_Port, LED_Pin, GPIO_PIN_RESET);/*Configure GPIO pin : LED_Pin */GPIO_InitStruct.Pin = LED_Pin;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;HAL_GPIO_Init(LED_GPIO_Port, &GPIO_InitStruct);/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}/* USER CODE BEGIN 4 *//* USER CODE END 4 *//* 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)
{/* init code for USB_DEVICE */MX_USB_DEVICE_Init();/* USER CODE BEGIN 5 *//* Infinite loop */for(;;){osDelay(1);}/* USER CODE END 5 */
}/* USER CODE BEGIN Header_StartTask_TASK_LED_FLASH */
/**
* @brief Function implementing the TASK_LED_FLASH thread.
* @param argument: Not used
* @retval None
*/
/* USER CODE END Header_StartTask_TASK_LED_FLASH */
void StartTask_TASK_LED_FLASH(void *argument)
{/* USER CODE BEGIN StartTask_TASK_LED_FLASH *//* Infinite loop */for(;;){osDelay(1000);HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);}/* USER CODE END StartTask_TASK_LED_FLASH */
}/* USER CODE BEGIN Header_StartTask_TASK_UART1 */
/**
* @brief Function implementing the TASK_UART1 thread.
* @param argument: Not used
* @retval None
*/
/* USER CODE END Header_StartTask_TASK_UART1 */
void StartTask_TASK_UART1(void *argument)
{/* USER CODE BEGIN StartTask_TASK_UART1 *//* Infinite loop */for(;;){osDelay(1);}/* USER CODE END StartTask_TASK_UART1 */
}/* USER CODE BEGIN Header_StartTask_TASK_USB_VCOM_H */
/**
* @brief Function implementing the TASK_USB_VCOM_H thread.
* @param argument: Not used
* @retval None
*/
/* USER CODE END Header_StartTask_TASK_USB_VCOM_H */
void StartTask_TASK_USB_VCOM_H(void *argument)
{/* USER CODE BEGIN StartTask_TASK_USB_VCOM_H */BaseType_t err_stu = pdFALSE;/* Infinite loop */for(;;){osDelay(8);err_stu = xSemaphoreTake(USB_VCOM_Mutex01Handle, USB_VCOM_xBlockTime);if(err_stu==pdTRUE){if(USB_CONN_STATUS()){usbprintstring("Task 1 Outputting\r\n");}xSemaphoreGive(USB_VCOM_Mutex01Handle);}}/* USER CODE END StartTask_TASK_USB_VCOM_H */
}/* USER CODE BEGIN Header_StartTask_TASK_USB_VCOM_L */
/**
* @brief Function implementing the TASK_USB_VCOM_L thread.
* @param argument: Not used
* @retval None
*/
/* USER CODE END Header_StartTask_TASK_USB_VCOM_L */
void StartTask_TASK_USB_VCOM_L(void *argument)
{/* USER CODE BEGIN StartTask_TASK_USB_VCOM_L */BaseType_t err_stu = pdFALSE;/* Infinite loop */for(;;){osDelay(5);err_stu = xSemaphoreTake(USB_VCOM_Mutex01Handle, USB_VCOM_xBlockTime);if(err_stu==pdTRUE){if(USB_CONN_STATUS()){usbprintstring("Task 2 Outputting\r\n");}osDelay(10);xSemaphoreGive(USB_VCOM_Mutex01Handle);}}/* USER CODE END StartTask_TASK_USB_VCOM_L */
}/*** @brief Period elapsed callback in non blocking mode* @note This function is called when TIM1 interrupt took place, inside* HAL_TIM_IRQHandler(). It makes a direct call to HAL_IncTick() to increment* a global variable "uwTick" used as application time base.* @param htim : TIM handle* @retval None*/
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{/* USER CODE BEGIN Callback 0 *//* USER CODE END Callback 0 */if (htim->Instance == TIM1) {HAL_IncTick();}/* USER CODE BEGIN Callback 1 *//* USER CODE END Callback 1 */
}/*** @brief This function is executed in case of error occurrence.* @retval None*/
void Error_Handler(void)
{/* USER CODE BEGIN Error_Handler_Debug *//* User can add his own implementation to report the HAL error return state */__disable_irq();while (1){}/* USER CODE END Error_Handler_Debug */
}#ifdef USE_FULL_ASSERT
/*** @brief Reports the name of the source file and the source line number* where the assert_param error has occurred.* @param file: pointer to the source file name* @param line: assert_param error line source number* @retval None*/
void assert_failed(uint8_t *file, uint32_t line)
{/* USER CODE BEGIN 6 *//* User can add his own implementation to report the file name and line number,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */例程下载
STM32 STM32CUBEIDE FreeRTOS操作教程（五）：mutex互斥信号量 例程
例程测试
例程测试效果如下：
–End–
