(STM32F4) IAP程式碼實現

IAP學習, 主要想了解實際上程式碼放在不同的Flash位置如何轉跳且執行。

我的應用程序只做了Pin12, Pin13 LED閃爍來分辨我的 App1 跟 App2的程式碼

App1 程式碼

 int main(void)
 {
     Delay_Init();
     LED_Config();
     EXIT_GPIO_Config();
     printf("\n--------------------------------------------------\n");
     printf("\n                 STM32F4 IAP APP1                 \n");
     printf("\n--------------------------------------------------\n");

         /* Flash unlock */
     FLASH_If_FlashUnlock();

     /* Test if User button on the Discovery kit is pressed */
     if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0) == Bit_RESET)
     {
         /* Check Vector Table: Test if user code is programmed starting from address
            "APPLICATION_ADDRESS" */
         if (((*(__IO uint32_t*)APPLICATION_ADDRESS) & 0x2FFE0000 ) == 0x20000000)
         {
           /* Jump to user application */
           JumpAddress = *(__IO uint32_t*) (APPLICATION_ADDRESS + );
           Jump_To_Application = (pFunction) JumpAddress;
           /* Initialize user application's Stack Pointer */
           __set_MSP(*(__IO uint32_t*) APPLICATION_ADDRESS);
           Jump_To_Application();
         }
     }

     while()
     {
         GPIOD->ODR |= GPIO_Pin_13;
         DelayMs();
         GPIOD->ODR &= ~GPIO_Pin_13;
         DelayMs();
     }

 }

App2 程式碼

 int main(void)
 {
     Delay_Init();
     LED_Config();
     EXIT_GPIO_Config();
     printf("\n--------------------------------------------------\n");
     printf("\n                 STM32F4 IAP APP2                 \n");
     printf("\n--------------------------------------------------\n");

     while()
     {
         GPIOD->ODR |= GPIO_Pin_12;
         DelayMs();
         GPIOD->ODR &= ~GPIO_Pin_12;
         DelayMs();
     }

 }

App1 轉跳 App2 經過一個IO的判斷去決定是否轉跳, 在App2的程式碼內也要指定程式碼放的位置。

分別是 system_stm32f4xx.c 理頭的 VECT_TAB_OFFSET 必須修改成App2的位置

Flash 位置也要改成從0x8010000開始

轉跳代碼

     /* Flash unlock */
     FLASH_If_FlashUnlock();

     /* Test if User button on the Discovery kit is pressed */
     if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0) == Bit_RESET)
     {
         /* Check Vector Table: Test if user code is programmed starting from address
            "APPLICATION_ADDRESS" */
         if (((*(__IO uint32_t*)APPLICATION_ADDRESS) & 0x2FFE0000 ) == 0x20000000)
         {
           /* Jump to user application */
           JumpAddress = *(__IO uint32_t*) (APPLICATION_ADDRESS + );
           Jump_To_Application = (pFunction) JumpAddress;
           /* Initialize user application's Stack Pointer */
           __set_MSP(*(__IO uint32_t*) APPLICATION_ADDRESS);
           Jump_To_Application();
         }
     }

第9行 APPLICATION_ADDRESS必須定義成APP2 Flash 存放的Address, 這段代碼在STM官方網站理頭都下載得到

#define APPLICATION_ADDRESS        (uint32_t)0x08010000
if (((*(__IO uint32_t*)APPLICATION_ADDRESS) & 0x2FFE0000 ) == 0x20000000)

在我的代碼裡頭, 在開機時只需要把 PA0 接到 GND, LED 閃爍的就是P12的LED。

App1 Code 位置從 0x8000000 開使堆疊(Stack)

App2 Code 位置從 0x8010000 開始堆疊(Stack)