工作环境:STM32CubeMX+Keil

相关环境准备这里就不介绍了。

bootloader是什么

  • bootloader就是单片机启动时候运行的一段小程序,这段程序负责单片机固件的更新,也就是单片机选择性的自己给自己下载程序。可以更新,可以不更新,更新的话,boot loader更新完程序后,跳转到新程序运行;不更新的话,boot loader直接跳转到原来的程序去运行。
  • boot loader更新完程序后并不擦除自己,下次启动后依然先运行boot loader程序,又可以选择性的更新或者不更新程序,所以boot loader就是用来管理单片机程序的更新。
  • 在实际的单片机工程项目中,如果加入了boot loader功能,就可以给单片机日后升级程序留出一个接口,方便日后单片机程序更新。当然,这就需要创建亮哥工程项目,一个位boot loader工程,一个为app工程。
  • bootloader工程生成的文件通常下载到ROM或者Flash中的首地址,这样可以保证上电后先运行boot loader程序。而app工程生成的文件则下载到ROM或者Flash中boot loader后面的地址中。也就是说,存在ROM或者Flash中的内容是分为两部分的。
  • 要实现同一个ROM或者Flash中保存两段程序,并且保证不能相互覆盖,则需要在下载程序时指定地址。如在keil中,可以进行如下调整(需要知道Flash的扇区地址)。
  • 升级流程

    在介绍升级流程之前。我们必须先搞清楚MCU型号对应的Flash分区情况,可以直接查看手册(当然,其实我们也可以在hal库代码中找到相关信息),如下图:

    因为上文说到,我们有两个程序需要下载到Flash,bootloader文件一般下载在最开始的地址,application一般在后面的地址。

    上图即为我们预定义的flash分配情况。我们一般是按照整个扇区进行利用的,这样便于擦除和写入。

  • bootloader从起始地址开始,这个没有疑问。我分配了扇区0给它(这个大小是具体情况而定)。

  • ota_flag这个是用于存放是否升级的标志位。存放在扇区1,ota_flag只占用4字节,当写入0x87654321的时候,表示需要升级,否则,无需升级。

  • application占用了两个连续的扇区,扇区2和扇区3。

  • ota_data也占用了两个连续的扇区,扇区4和扇区5。

  • [外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-oH0MLjqQ-1686299396663)(C:\Users\DELL\AppData\Roaming\Typora\typora-user-images\image-20230609161215006.png)]

    代码示例

    #ifndef BOOTLOADER_H
    #define BOOTLOADER_H
    
    #ifdef __cpluscplus
    extern "c"
    {
    #endif
    
    #define FLASH_SECTOR_STEP_SIZE  (128*1024)
    #define FLASH_SECTOR_0_ADDRESS  (0x08000000)
    
    #define MCU_OTA_FLAG_ADDRESS (FLASH_SECTOR_0_ADDRESS+ FLASH_SECTOR_STEP_SIZE * FLASH_SECTOR_1)
    #define APPLICATION_ADDRESS  (FLASH_SECTOR_0_ADDRESS+ FLASH_SECTOR_STEP_SIZE * FLASH_SECTOR_2)
    
    #define MCU_OTA_DATA_ADDRESS (FLASH_SECTOR_0_ADDRESS+ FLASH_SECTOR_STEP_SIZE * FLASH_SECTOR_4)
    #define MCU_OTA_FLAG_VALUE   (0x87654321)
    
    int erase_mcu_ota_flag();
    int write_mcu_ota_flag();
    int erase_application_sectors();
    int write_application_sectors();
    int mcu_reset();
    
    
    #ifdef __cpluscplus
    }
    #endif
    #endif
    
    #include "bootloader.h"
    #include "stm32h7xx_hal.h"
    #include "stm32h7xx_hal_flash.h"
    #include <stdint.h>
    
    
    int erase_mcu_ota_flag()
    {
    	  int ret=0;
        uint32_t SectorError = 0;
    	
    		FLASH_EraseInitTypeDef sector;
    		sector.TypeErase = FLASH_TYPEERASE_SECTORS;
    		sector.VoltageRange = FLASH_VOLTAGE_RANGE_3;
    		sector.Sector = FLASH_SECTOR_1;
    		sector.NbSectors = 1;
    	
    		HAL_FLASH_Unlock();
    		ret = HAL_FLASHEx_Erase(&sector, &SectorError);
    		HAL_FLASH_Lock();
    	  return ret;
    }
    
    int write_mcu_ota_flag()
    {
    	  int ret=0;
    		HAL_FLASH_Unlock();
    		ret = HAL_FLASH_Program(FLASH_PSIZE_WORD, MCU_OTA_FLAG_ADDRESS, MCU_OTA_FLAG_VALUE);
    		HAL_FLASH_Lock();
    	  return ret;
    }
    
    int erase_application_sectors()
    {
    	  int ret=0;
        uint32_t SectorError = 0;
    	
    		FLASH_EraseInitTypeDef sector;
    		sector.TypeErase = FLASH_TYPEERASE_SECTORS;
    		sector.VoltageRange = FLASH_VOLTAGE_RANGE_3;
    		sector.Sector = FLASH_SECTOR_2;
    		sector.NbSectors = 2;
    	
    		HAL_FLASH_Unlock();
    		ret = HAL_FLASHEx_Erase(&sector, &SectorError);
    		HAL_FLASH_Lock();
    	  return ret;
    }
    
    int write_application_sectors()
    {
    	  int ret=0;
    		HAL_FLASH_Unlock();
    	  for(int i=0;i<MCU_OTA_DATA_ADDRESS;i+=4)
    	  {
    			ret = HAL_FLASH_Program(FLASH_PSIZE_WORD, APPLICATION_ADDRESS+i, *(__IO uint32_t*)(MCU_OTA_DATA_ADDRESS+i));
    	  }
    		HAL_FLASH_Lock();
    	  return ret;
    }
    
    int mcu_reset()
    {
    	 __set_FAULTMASK(1);
       __NVIC_SystemReset();
    }
    
    /* 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 "usart.h"
    #include "gpio.h"
    
    /* Private includes ----------------------------------------------------------*/
    /* USER CODE BEGIN Includes */
    #include "bootloader.h"
    #include <stdio.h>
    /* USER CODE END Includes */
    
    /* Private typedef -----------------------------------------------------------*/
    /* USER CODE BEGIN PTD */
    typedef void (*pFunction)();
    /* 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 */
    
      /* 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 */
    	uint32_t JumpAddress;
        pFunction Jump_To_Application;
    	if(*(__IO uint32_t*)MCU_OTA_FLAG_ADDRESS != MCU_OTA_FLAG_VALUE)
    	{
    		  JumpAddress = *(__IO uint32_t*)(APPLICATION_ADDRESS+4);
          Jump_To_Application = (pFunction)JumpAddress;
    
          __set_MSP(*(__IO uint32_t*)APPLICATION_ADDRESS);
          Jump_To_Application();
    	}
    	else
    	{ 
    		  printf("mcu_ota");  
    		
    		  erase_application_sectors();
    		
    		  write_application_sectors();
    		
    		  erase_mcu_ota_flag();
    		
    		  mcu_reset();
    	}
    	
      /* USER CODE END 2 */
    
      /* 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};
    
      /** Supply configuration update enable
      */
      HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
    
      /** Configure the main internal regulator output voltage
      */
      __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);
    
      while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}
    
      /** 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 = 1;
      RCC_OscInitStruct.PLL.PLLN = 75;
      RCC_OscInitStruct.PLL.PLLP = 2;
      RCC_OscInitStruct.PLL.PLLQ = 2;
      RCC_OscInitStruct.PLL.PLLR = 2;
      RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_3;
      RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
      RCC_OscInitStruct.PLL.PLLFRACN = 0;
      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_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;
      RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
      RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
      RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV2;
      RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;
      RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;
      RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;
      RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;
    
      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 */
    

    总结

    关于地址跳转部分,可以参考STM32 Bootloader程序中Jump2App函数分析

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