flash基本規劃

為實現IAP升級，一般將flash規劃成如上區域。
bootloader: 系統引導
app: 主程序運行的地方
update: 新的主程序固件存放的地方
這里給bootloader預留16K的空間，所以APP所在地址是0x08004000，編譯APP時，要注意將中斷向量表的偏移地址設置為0x4000

bootloader要完成的功能

根據以上描述，bootloader應有以下功能

跳轉功能，可以跳轉到app區執行主程序

固件搬運功能，因為固件中斷向量偏移是固定的0x4000，所以如果有新固件，需要將新固件轉移到app區再跳轉（APP區地址偏移需和中斷向量偏移對應）

bootloader實現

根據上節分析，實現bootloader要有如下工作：

編寫讀寫內部flash的接口

編寫跳轉到指定地址運行程序的代碼

• 根據ST官方例程實現的flash操作接口：
  擦除操作

// flash只能按頁擦除。第一個參數是待擦除的起始頁，第二個參數是要擦除的頁數 uint32_t FLASH_If_Erase(uint32_t start_page, uint8_t pages) {uint32_t PageError = 0;FLASH_EraseInitTypeDef pEraseInit;HAL_StatusTypeDef status = HAL_OK;/* Unlock the Flash to enable the flash control register access *************/ HAL_FLASH_Unlock();pEraseInit.TypeErase = FLASH_TYPEERASE_PAGES;pEraseInit.PageAddress = start_page;pEraseInit.Banks = FLASH_BANK_1;pEraseInit.NbPages = pages;status = HAL_FLASHEx_Erase(&pEraseInit, &PageError);/* Lock the Flash to disable the flash control register access (recommendedto protect the FLASH memory against possible unwanted operation) *********/HAL_FLASH_Lock();if (status != HAL_OK){/* Error occurred while page erase */return FLASHIF_ERASEKO;}return FLASHIF_OK; }

寫flash

#define UPDATE_APP_ADDRESS (uint32_t)0x0802C000 /* ADDR_FLASH_PAGE_88 */ #define APP_ADDRESS (uint32_t)0x08004000 uint32_t FLASH_If_Write(uint32_t destination, uint32_t *p_source, uint32_t length) {uint32_t i = 0;/* Unlock the Flash to enable the flash control register access *************/HAL_FLASH_Unlock();for (i = 0; (i < length) && (destination <= (USER_FLASH_END_ADDRESS-4)); i++){/* Device voltage range supposed to be [2.7V to 3.6V], the operation willbe done by word */ if (HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, destination, *(uint32_t*)(p_source+i)) == HAL_OK) {/* Check the written value */if (*(uint32_t*)destination != *(uint32_t*)(p_source+i)){/* Flash content doesn't match SRAM content */return(FLASHIF_WRITINGCTRL_ERROR);}/* Increment FLASH destination address */destination += 4;}else{/* Error occurred while writing data in Flash memory */return (FLASHIF_WRITING_ERROR);}}/* Lock the Flash to disable the flash control register access (recommendedto protect the FLASH memory against possible unwanted operation) *********/HAL_FLASH_Lock();return (FLASHIF_OK); }

• 固件轉移

void AppMove(void) {// 新固件區的首個字是存放固件大小的uint32_t file_size = *(uint32_t*)UPDATE_APP_ADDRESS;uint32_t pages_use = 0;uint32_t* data_ptr = NULL;uint32_t file_size_word = 0;if (file_size != 0xffffffff) {printf("move app\n");data_ptr = (uint32_t*)(UPDATE_APP_ADDRESS + 4);// 計算需要擦除的頁數pages_use = file_size / FLASH_PAGE_SIZE + 1;printf("size: %d pages_use: %d\n", file_size, pages_use);file_size_word = file_size / 4;FLASH_If_Erase(APP_ADDRESS, pages_use);// 讀取UPDATA區并寫入APP跳轉區域FLASH_If_Write(APP_ADDRESS, data_ptr, file_size_word);// 擦除UPDATA區FLASH_If_Erase(UPDATE_APP_ADDRESS, pages_use);} else {printf("no new app\n");} }

• 程序跳轉

typedef void (*pFunction)(void); void AppJump(void) {printf("jump\n");if (((*(__IO uint32_t*)APP_ADDRESS) & 0x2FFE0000 ) == 0x20000000) {uint32_t jump_addr = *(__IO uint32_t*)(APP_ADDRESS + 4);pFunction jump_to_app = (pFunction)jump_addr;__set_MSP(*(__IO uint32_t*)APP_ADDRESS);__disable_irq();jump_to_app();} }

• main.c

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_USART3_UART_Init();/* USER CODE BEGIN 2 */AppMove();AppJump();/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */ }

bool就完成了 IAP參考這里

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