125.4.15中断接收数据原理

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: 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 */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: 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__ */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: 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 */

/* USER CODE END Includes */

extern UART_HandleTypeDef huart1;

/* USER CODE BEGIN Private defines */

/* 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__ */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: Core/Inc/stm32f1xx_it.h
 * ======================================================================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    stm32f1xx_it.h
  * @brief   This file contains the headers of the interrupt handlers.
  ******************************************************************************
  * @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 __STM32F1xx_IT_H
#define __STM32F1xx_IT_H

#ifdef __cplusplus
 extern "C" {
#endif

/* 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 NMI_Handler(void);
void HardFault_Handler(void);
void MemManage_Handler(void);
void BusFault_Handler(void);
void UsageFault_Handler(void);
void SVC_Handler(void);
void DebugMon_Handler(void);
void PendSV_Handler(void);
void SysTick_Handler(void);
void USART1_IRQHandler(void);
/* USER CODE BEGIN EFP */

/* USER CODE END EFP */

#ifdef __cplusplus
}
#endif

#endif /* __STM32F1xx_IT_H */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: 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_IT[5]; /* 接收 4 字节命令，第 5 字节保留为字符串结束符。 */
/* 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 */
  HAL_UART_Receive_IT(&huart1, UART_Recv_IT, 4); /* 首次登记固定 4 字节的中断接收任务。 */
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
	  HAL_UART_Transmit_IT(&huart1, "i am wfeng\n", strlen("i am wfeng\n")); /* 异步启动发送，未完成时再次调用可能返回忙。 */
	  HAL_Delay(1000);
	/* 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 */
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	  if(huart ==&huart1) /* 所有 UART 共用回调，先判断来源。 */
	  {
		  if(strcmp("LED1", (char *)UART_Recv_IT)==0)
		  {
			  HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);
			  memset(UART_Recv_IT, '\0', 5);
		  }
		  if(!strcmp("LED2", (char *)UART_Recv_IT))
		  {
			  HAL_GPIO_TogglePin(LED2_GPIO_Port, LED2_Pin);
			  memset(UART_Recv_IT, '\0', 5);
		  }
		  HAL_UART_Receive_IT(&huart1, UART_Recv_IT, 4); /* 完成回调中重新登记，才能持续接收。 */
	  }

}
/* 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 */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: 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 */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: 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 */

/* 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);

    /* USART1 interrupt Init */
    HAL_NVIC_SetPriority(USART1_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(USART1_IRQn);
  /* 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);

    /* USART1 interrupt Deinit */
    HAL_NVIC_DisableIRQ(USART1_IRQn);
  /* USER CODE BEGIN USART1_MspDeInit 1 */

  /* USER CODE END USART1_MspDeInit 1 */
  }
}

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/* ========================================================================
 * Project: CubeIDE/04UART_IT
 * File: Core/Src/stm32f1xx_it.c
 * ======================================================================== */
/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    stm32f1xx_it.c
  * @brief   Interrupt Service Routines.
  ******************************************************************************
  * @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 "stm32f1xx_it.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */

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

/* USER CODE END TD */

/* 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 */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/* External variables --------------------------------------------------------*/
extern UART_HandleTypeDef huart1;
/* USER CODE BEGIN EV */

/* USER CODE END EV */

/******************************************************************************/
/*           Cortex-M3 Processor Interruption and Exception Handlers          */
/******************************************************************************/
/**
  * @brief This function handles Non maskable interrupt.
  */
void NMI_Handler(void)
{
  /* USER CODE BEGIN NonMaskableInt_IRQn 0 */

  /* USER CODE END NonMaskableInt_IRQn 0 */
  /* USER CODE BEGIN NonMaskableInt_IRQn 1 */
   while (1)
  {
  }
  /* USER CODE END NonMaskableInt_IRQn 1 */
}

/**
  * @brief This function handles Hard fault interrupt.
  */
void HardFault_Handler(void)
{
  /* USER CODE BEGIN HardFault_IRQn 0 */

  /* USER CODE END HardFault_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_HardFault_IRQn 0 */
    /* USER CODE END W1_HardFault_IRQn 0 */
  }
}

/**
  * @brief This function handles Memory management fault.
  */
void MemManage_Handler(void)
{
  /* USER CODE BEGIN MemoryManagement_IRQn 0 */

  /* USER CODE END MemoryManagement_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_MemoryManagement_IRQn 0 */
    /* USER CODE END W1_MemoryManagement_IRQn 0 */
  }
}

/**
  * @brief This function handles Prefetch fault, memory access fault.
  */
void BusFault_Handler(void)
{
  /* USER CODE BEGIN BusFault_IRQn 0 */

  /* USER CODE END BusFault_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_BusFault_IRQn 0 */
    /* USER CODE END W1_BusFault_IRQn 0 */
  }
}

/**
  * @brief This function handles Undefined instruction or illegal state.
  */
void UsageFault_Handler(void)
{
  /* USER CODE BEGIN UsageFault_IRQn 0 */

  /* USER CODE END UsageFault_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_UsageFault_IRQn 0 */
    /* USER CODE END W1_UsageFault_IRQn 0 */
  }
}

/**
  * @brief This function handles System service call via SWI instruction.
  */
void SVC_Handler(void)
{
  /* USER CODE BEGIN SVCall_IRQn 0 */

  /* USER CODE END SVCall_IRQn 0 */
  /* USER CODE BEGIN SVCall_IRQn 1 */

  /* USER CODE END SVCall_IRQn 1 */
}

/**
  * @brief This function handles Debug monitor.
  */
void DebugMon_Handler(void)
{
  /* USER CODE BEGIN DebugMonitor_IRQn 0 */

  /* USER CODE END DebugMonitor_IRQn 0 */
  /* USER CODE BEGIN DebugMonitor_IRQn 1 */

  /* USER CODE END DebugMonitor_IRQn 1 */
}

/**
  * @brief This function handles Pendable request for system service.
  */
void PendSV_Handler(void)
{
  /* USER CODE BEGIN PendSV_IRQn 0 */

  /* USER CODE END PendSV_IRQn 0 */
  /* USER CODE BEGIN PendSV_IRQn 1 */

  /* USER CODE END PendSV_IRQn 1 */
}

/**
  * @brief This function handles System tick timer.
  */
void SysTick_Handler(void)
{
  /* USER CODE BEGIN SysTick_IRQn 0 */

  /* USER CODE END SysTick_IRQn 0 */
  HAL_IncTick();
  /* USER CODE BEGIN SysTick_IRQn 1 */

  /* USER CODE END SysTick_IRQn 1 */
}

/******************************************************************************/
/* STM32F1xx Peripheral Interrupt Handlers                                    */
/* Add here the Interrupt Handlers for the used peripherals.                  */
/* For the available peripheral interrupt handler names,                      */
/* please refer to the startup file (startup_stm32f1xx.s).                    */
/******************************************************************************/

/**
  * @brief This function handles USART1 global interrupt.
  */
void USART1_IRQHandler(void)
{
  /* USER CODE BEGIN USART1_IRQn 0 */

  /* USER CODE END USART1_IRQn 0 */
  HAL_UART_IRQHandler(&huart1); /* 读取 USART 状态并交给 HAL 的中断状态机。 */
  /* USER CODE BEGIN USART1_IRQn 1 */

  /* USER CODE END USART1_IRQn 1 */
}

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

一、知识回顾

轮询接收在 HAL_UART_Receive() 内等待 RXNE，并使用同一 tickstart 控制整次接收超时。中断接收则提前保存缓冲区和计数器，收到字节时才打断 CPU；启动函数本身立即返回，没有 Timeout 参数。

二、中断接收原理分析

2.1 中断接收原理分析之main.c分析

应用层需要关注两个入口：

HAL_UART_Receive_IT(&huart1, UART_Recv_IT, 4);

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
    /* 收满4个数据元素后执行 */
}

第一个接口登记一次固定长度接收，第二个接口处理完成事件。回调末尾再次启动接收，才能形成连续工作。

2.2 中断接收原理分析之接收函数

HAL_UART_Receive_IT() 先确认 RxState == READY、缓冲区非空且 Size != 0，再调用：

UART_Start_Receive_IT(huart, pData, Size);

Start 函数完成四件事：

1. pRxBuffPtr = pData，记住目标内存地址；
2. RxXferSize = RxXferCount = Size；
3. 清错误码并将接收状态设为 BUSY_RX；
4. 打开校验、错误和 RXNE 中断。

启动接口只配置状态，不读取数据。真正的读 DR 操作发生在后续 IRQ 中。

2.3 中断接收原理分析之UART_HandleTypeDef结构体

UART_HandleTypeDef 把硬件实例、初始化参数和一次传输的运行状态集中起来：

成员	作用
Instance	指向 USART1、USART2 等寄存器组
Init	波特率、字长、停止位、校验、收发模式
pRxBuffPtr	当前要写入的缓冲区位置
RxXferSize	本次接收总元素数
RxXferCount	尚未接收的元素数
RxState	READY、BUSY_RX 等状态
ErrorCode	PE、NE、FE、ORE、DMA 等错误
hdmarx/hdmatx	DMA 模式使用的句柄

Start 函数开启的相关控制位：

控制位	所在寄存器	含义
RXNEIE	USART_CR1	RXNE/ORE 中断允许
PEIE	USART_CR1	校验错误中断允许
EIE	USART_CR3	帧错误、噪声、溢出错误中断允许

只有启用校验时才需要 PEIE。RXNEIE 是每个接收数据元素进入中断处理的关键。

2.4 中断接收原理分析之回调函数

硬件到回调的路径：

flowchart TD
    A[RX引脚收到完整字符] --> B[移位寄存器把数据送入DR]
    B --> C[SR.RXNE置1]
    C --> D{CR1.RXNEIE=1且NVIC已使能?}
    D -- 否 --> E[等待软件读取/可能产生ORE]
    D -- 是 --> F[Cortex-M3查中断向量表]
    F --> G[USART1_IRQHandler]
    G --> H[HAL_UART_IRQHandler]
    H --> I[UART_Receive_IT读取DR]
    I --> J{RxXferCount减到0?}
    J -- 否 --> A
    J -- 是 --> K[HAL_UART_RxCpltCallback]

启动文件中的向量表保存 USART1_IRQHandler 地址；stm32f1xx_it.c 提供函数实体并调用 HAL。手动移植工程时漏掉这一层，即使接收接口和 NVIC 都配置正确，也无法进入 HAL 处理。

2.5 中断接收原理分析之main函数

若 Size=4：

初始：pRxBuffPtr = &buffer[0]，RxXferCount = 4
第1字节：写buffer[0]，指针+1，Count=3
第2字节：写buffer[1]，指针+1，Count=2
第3字节：写buffer[2]，指针+1，Count=1
第4字节：写buffer[3]，指针+1，Count=0 → 完成回调

main() 调用接收接口后可以继续运行主循环。变量 pData 只是启动接口的参数，HAL 把它保存到句柄的 pRxBuffPtr，因此缓冲区在整个接收完成前必须始终有效，不能是已经退出作用域的临时数组。

2.6 中断接收原理分析之接收数据处理函数

HAL_UART_IRQHandler() 首先读取 SR、CR1、CR3。没有错误且“RXNE 已置位、RXNEIE 已允许”时，调用内部 UART_Receive_IT()：

*pdata8bits = (uint8_t)(huart->Instance->DR & 0x00FF);
huart->pRxBuffPtr += 1U;

if (--huart->RxXferCount == 0U)
{
    __HAL_UART_DISABLE_IT(huart, UART_IT_RXNE);
    __HAL_UART_DISABLE_IT(huart, UART_IT_PE);
    __HAL_UART_DISABLE_IT(huart, UART_IT_ERR);
    huart->RxState = HAL_UART_STATE_READY;
    HAL_UART_RxCpltCallback(huart);
}

每个字节产生一次 IRQ，但用户完成回调只在 Count 归零时调用一次。若发生 ORE，HAL 会将其视为阻塞性错误、结束当前接收并调用 HAL_UART_ErrorCallback()；应用应在错误回调中记录原因并考虑重新启动。

2.7 中断接收原理分析之回调函数

HAL 驱动提供一个 __weak 的空回调。应用在 main.c 定义同名的非弱函数后，链接器选择应用实现。回调中应：

1. 判断触发源是否为目标 USART；
2. 只执行短小的数据确认或置标志；
3. 保证字符串终止或按长度比较；
4. 清理必要状态；
5. 重新启动下一轮接收。

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
    if (huart->Instance == USART1)
    {
        UART_Recv_IT[4] = '\0';
        /* 识别4字节命令 */
        memset(UART_Recv_IT, 0, sizeof(UART_Recv_IT));
        HAL_UART_Receive_IT(&huart1, UART_Recv_IT, 4);
    }
}

中断里不应长时间 printf()、阻塞发送或延时。普通中断的根本限制仍是固定 Size；不定长数据可以使用逐字节状态机，或空闲事件配合 DMA。