
这个是实现后的效果,可以看到已经没有中断的效果了

这个是拦截前的效果可以看到电平是在变化的
实现原理非常简单:一句话搞定:
if(TIM2->CNT==TIM2->ARR-5)TIM2->CNT-=5;
以下是完整的代码:是用来补充说明和筹字数的
- /* 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.
- *
- ******************************************************************************
- */
- /* USER CODE END Header */
- /* Includes ------------------------------------------------------------------*/
- #include "main.h"
- #include "tim.h"
- #include "gpio.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 PV */
-
- /* 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 */
- uint8_t sz[]="hello nice to meet you";
- /* 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_TIM2_Init();
- /* USER CODE BEGIN 2 */
- HAL_TIM_Base_Start_IT(&htim2);
-
- /* USER CODE END 2 */
-
- /* Infinite loop */
- /* USER CODE BEGIN WHILE */
- while (1)
- {
- /* USER CODE END WHILE */
- if(TIM2->CNT==TIM2->ARR-5)TIM2->CNT-=5;
- /* 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_HSI;
- RCC_OscInitStruct.HSIState = RCC_HSI_ON;
- RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
- RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
- RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
- RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL2;
- 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_0) != 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 */
这就表明了,单片机里面是可以植入病毒的,或者不算病毒,里面的代码也是具有修改破坏的可能性,假设在一个中断里面插入这么一句,理论上除了异常不能被屏蔽,所有的中断都可以屏蔽,导致的结果就是:插入外设例如USB没有反应,识别不出来,因为外设是通过中断来识别的,那样那个单片机就没有用处了,好像就废了可以扔掉了,不过这个东西可以用来保护单片机不被修改,
假设稍微修改一下,可以输入密码,用来加密