113.4.3串口数据接收

/* ==================== Core\Inc\main.h ==================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.h
  * @brief          : Header for main.c file.
  *                   This file contains the common defines of the application.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 */

/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __MAIN_H
#define __MAIN_H

#ifdef __cplusplus
extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include "stm32f1xx_hal.h"

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

/* USER CODE END Includes */

/* Exported types ------------------------------------------------------------*/
/* USER CODE BEGIN ET */

/* USER CODE END ET */

/* Exported constants --------------------------------------------------------*/
/* USER CODE BEGIN EC */

/* USER CODE END EC */

/* Exported macro ------------------------------------------------------------*/
/* USER CODE BEGIN EM */

/* USER CODE END EM */

/* Exported functions prototypes ---------------------------------------------*/
void Error_Handler(void);

/* USER CODE BEGIN EFP */

/* USER CODE END EFP */

/* Private defines -----------------------------------------------------------*/
#define LED2_Pin GPIO_PIN_5
#define LED2_GPIO_Port GPIOE
#define LED1_Pin GPIO_PIN_5
#define LED1_GPIO_Port GPIOB

/* USER CODE BEGIN Private defines */

/* USER CODE END Private defines */

#ifdef __cplusplus
}
#endif

#endif /* __MAIN_H */

/* ==================== Core\Inc\gpio.h ==================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    gpio.h
  * @brief   This file contains all the function prototypes for
  *          the gpio.c file
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 */
/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __GPIO_H__
#define __GPIO_H__

#ifdef __cplusplus
extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include "main.h"

/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* USER CODE BEGIN Private defines */

/* USER CODE END Private defines */

void MX_GPIO_Init(void);

/* USER CODE BEGIN Prototypes */

/* USER CODE END Prototypes */

#ifdef __cplusplus
}
#endif
#endif /*__ GPIO_H__ */


/* ==================== Core\Inc\usart.h ==================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    usart.h
  * @brief   This file contains all the function prototypes for
  *          the usart.c file
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 */
/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __USART_H__
#define __USART_H__

#ifdef __cplusplus
extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include "main.h"

/* USER CODE BEGIN Includes */
#include <stdio.h>
/* USER CODE END Includes */

extern UART_HandleTypeDef huart1;

/* USER CODE BEGIN Private defines */
extern uint8_t u_buf[256];
#define printf(...)  HAL_UART_Transmit(&huart1, (uint8_t *)u_buf, sprintf((char*)u_buf, __VA_ARGS__), 0xffff)
/* USER CODE END Private defines */

void MX_USART1_UART_Init(void);

/* USER CODE BEGIN Prototypes */

/* USER CODE END Prototypes */

#ifdef __cplusplus
}
#endif

#endif /* __USART_H__ */


/* ==================== Core\Src\main.c ==================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 "main.h"
#include "usart.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <string.h>
/* 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 PV */
uint8_t UART_Recv[5];
uint8_t DHT11_Buf[30];
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 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_USART1_UART_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {

	  HAL_UART_Receive(&huart1, UART_Recv, 4, 1000);
	  if(strcmp("LED1", (char *)UART_Recv)==0)
	  {
		  HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);
		  memset(UART_Recv, '\0', 4);
	  }
	  if(!strcmp("LED2", (char *)UART_Recv))
	  {
		  HAL_GPIO_TogglePin(LED2_GPIO_Port, LED2_Pin);
		  memset(UART_Recv, '\0', 4);
	  }
	  sprintf((char *)DHT11_Buf,"H2:%f T2:%f\n",30.1,36.5);
	  HAL_UART_Transmit(&huart1, (char *)DHT11_Buf, strlen(DHT11_Buf), 1000);
	  printf("Hellow world wfeng %d!\n",123);


    /* 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};

  /** 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.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  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();
  }
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @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 */

/* ==================== Core\Src\gpio.c ==================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    gpio.c
  * @brief   This file provides code for the configuration
  *          of all used GPIO pins.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 "gpio.h"

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/*----------------------------------------------------------------------------*/
/* Configure GPIO                                                             */
/*----------------------------------------------------------------------------*/
/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/** Configure pins as
        * Analog
        * Input
        * Output
        * EVENT_OUT
        * EXTI
*/
void MX_GPIO_Init(void)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOE_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(LED2_GPIO_Port, LED2_Pin, GPIO_PIN_SET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(LED1_GPIO_Port, LED1_Pin, GPIO_PIN_SET);

  /*Configure GPIO pin : PtPin */
  GPIO_InitStruct.Pin = LED2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LED2_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : PtPin */
  GPIO_InitStruct.Pin = LED1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LED1_GPIO_Port, &GPIO_InitStruct);

}

/* USER CODE BEGIN 2 */

/* USER CODE END 2 */

/* ==================== Core\Src\usart.c ==================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    usart.c
  * @brief   This file provides code for the configuration
  *          of the USART instances.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 "usart.h"

/* USER CODE BEGIN 0 */
uint8_t u_buf[256];
/* USER CODE END 0 */

UART_HandleTypeDef huart1;

/* USART1 init function */

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 */

}

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(uartHandle->Instance==USART1)
  {
  /* USER CODE BEGIN USART1_MspInit 0 */

  /* USER CODE END USART1_MspInit 0 */
    /* USART1 clock enable */
    __HAL_RCC_USART1_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**USART1 GPIO Configuration
    PA9     ------> USART1_TX
    PA10     ------> USART1_RX
    */
    GPIO_InitStruct.Pin = GPIO_PIN_9;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = GPIO_PIN_10;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* USER CODE BEGIN USART1_MspInit 1 */

  /* USER CODE END USART1_MspInit 1 */
  }
}

void HAL_UART_MspDeInit(UART_HandleTypeDef* uartHandle)
{

  if(uartHandle->Instance==USART1)
  {
  /* USER CODE BEGIN USART1_MspDeInit 0 */

  /* USER CODE END USART1_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_USART1_CLK_DISABLE();

    /**USART1 GPIO Configuration
    PA9     ------> USART1_TX
    PA10     ------> USART1_RX
    */
    HAL_GPIO_DeInit(GPIOA, GPIO_PIN_9|GPIO_PIN_10);

  /* USER CODE BEGIN USART1_MspDeInit 1 */

  /* USER CODE END USART1_MspDeInit 1 */
  }
}

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

一、项目配置与代码讲解

本节使用 STM32CubeMX/CubeIDE 配置 USART1，以轮询方式接收电脑串口助手发送的 4 字节命令。收到 LED1 或 LED2 后，分别翻转 PB5、PE5 对应的 LED。

1.1 配置RCC

在 RCC 中启用外部高速时钟 HSE。开发板使用 8 MHz 外部晶振，经 PLL 倍频后得到系统时钟。若实际硬件没有外部晶振，就不能照搬 HSE 配置，应按板卡时钟源调整。

调试接口建议在 SYS 中选择 Serial Wire，保留 SWDIO、SWCLK 两根调试线。若错误地关闭调试口，常见恢复方法是“Connect under reset”后重新烧录，并非通过串口自动改回设置。

1.2 配置时钟

本工程将系统时钟配置为 72 MHz，APB2 上的 USART1 获得相应外设时钟。CubeMX 会根据时钟树计算串口分频值；USART1 的波特率配置为 115200。

1.3 配置项目管理器

在 Project Manager 中设置工程名、保存路径和 STM32CubeIDE 工具链，然后生成初始化代码。用户代码应写在 USER CODE BEGIN/END 区域内，避免再次生成代码时被覆盖。

1.4 配置USART1

USART1 选择 Asynchronous 模式，常用参数为：

参数	设置
Baud Rate	115200 bit/s
Word Length	8 Bits
Parity	None
Stop Bits	1
Hardware Flow Control	None
Mode	TX and RX

本开发板的 USART1 使用 PA9 发送、PA10 接收，板载 CH340C 已将它们连接到 USB。数据路径为：

电脑USB → CH340C TXD → PA10/USART1_RX → 接收数据寄存器
电脑USB ← CH340C RXD ← PA9 /USART1_TX ← 发送数据寄存器

两端必须使用相同的波特率、数据位、校验位和停止位，否则可能产生乱码、帧错误或完全收不到数据。

1.5 配置灯所使用的GPIO端口

LED1 使用 PB5，LED2 使用 PE5，均配置为推挽输出、默认高电平。由于 LED 阳极接 3.3 V、阴极经电阻接 GPIO，所以输出低电平时点亮，高电平时熄灭。

1.6 项目代码分析

程序定义 5 字节缓冲区 uint8_t UART_Recv[5];。前 4 字节保存命令，第 5 字节维持 '\0'，使缓冲区可以交给 strcmp() 按 C 字符串处理。

1.6.1 GPIO库函数介绍

HAL_GPIO_TogglePin(GPIOx, GPIO_Pin) 翻转指定 GPIO 的输出状态，例如：

HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);
HAL_GPIO_TogglePin(LED2_GPIO_Port, LED2_Pin);

第一个参数是 GPIO 端口，第二个参数是引脚位掩码。PB5 和 PE5 属于不同端口，不能只改引脚编号而忽略端口。

1.6.2 三种USART接收方式介绍

HAL 常见接收接口如下：

方式	HAL接口	CPU特点	适用场景
轮询	HAL_UART_Receive()	等待期间反复查询状态	数据少、逻辑简单
普通中断	HAL_UART_Receive_IT()	每个接收事务完成后回调	固定长度、小数据量
DMA	HAL_UART_Receive_DMA()	DMA搬运固定数量数据	连续或较大数据
空闲事件+DMA	HAL_UARTEx_ReceiveToIdle_DMA()	长度可变，空闲时通知	不定长数据帧

轮询函数并不是调用后立刻取得任意数量的数据。它会等待 Size 个字节全部到齐，或者超时/出错后返回，返回值可能为 HAL_OK、HAL_TIMEOUT、HAL_BUSY 或 HAL_ERROR。

1.6.2.1 例题: USART接收方式应用

核心调用：

HAL_StatusTypeDef status;
status = HAL_UART_Receive(&huart1, UART_Recv, 4, 1000);

参数依次表示 USART1 句柄、接收缓冲区、需要接收的字节数和最长等待时间 1000 ms。只有 status == HAL_OK 时，4 个字节才确定完整有效。若直接忽略返回值，超时后的旧数据可能被当成新命令。

1.6.2.2 字符串比较函数百度百科

strcmp(a, b) 从头逐字节比较两个以 '\0' 结尾的字符串：

• 返回 0：两个字符串相等；
• 返回负值：第一个不同字符中，a 小于 b；
• 返回正值：第一个不同字符中，a 大于 b。

strcmp("LED1", (char *)UART_Recv) == 0 和 !strcmp(...) 都表示相等。接收区必须有终止符，否则函数会继续越界读取。

1.6.2.3 内存初始化函数百度百科

memset(ptr, value, count) 将从 ptr 开始的 count 个字节设成同一个字节值。清空缓冲区可写：

memset(UART_Recv, 0, sizeof(UART_Recv));

第二个参数按字节填充，因此 memset(array, 1, sizeof(array)) 并不会把整型数组的每个元素设置成整数 1。

1.6.2.4 应用案例

更稳妥的轮询处理结构如下：

if (HAL_UART_Receive(&huart1, UART_Recv, 4, 1000) == HAL_OK)
{
    UART_Recv[4] = '\0';

    if (strcmp("LED1", (char *)UART_Recv) == 0)
    {
        HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);
    }
    else if (strcmp("LED2", (char *)UART_Recv) == 0)
    {
        HAL_GPIO_TogglePin(LED2_GPIO_Port, LED2_Pin);
    }

    memset(UART_Recv, 0, sizeof(UART_Recv));
}

这里使用 else if，保证一条命令只进入一个分支。该例仍存在固定 4 字节的限制：如果串口助手附加回车换行，\r\n 会留在接收流中并影响下一次接收，测试时应关闭自动换行，或设计带帧头、长度和校验的数据包。