快报:浅析STM32单片机的启动文件

2023-06-12 17:25:53 来源:电子工程师联盟

今天来总结的stm32基础知识是启动文件相关。要想对是stm32单片机有个深入的理解,那么启动文件就是一个绕不过去的坎。

一、什么是启动文件


(资料图片)

简单说,启动文件是在单片机用户程序执行之前,执行的一段汇编代码。这段汇编代码是执行用户程序之前的一个准备环节。文件名以.s的格式来命名,表明其是汇编文件。启动文件,不用自己进行编写,参照一些伪指令定义,能够看得懂,在实际开发中如果涉及到一些改动,能够简单修改就可以了。

二、启动文件所讲内容概要

那么,启动文件里面主要讲的是什么内容呢?分为如下5个方面:

1.堆栈空间的定义;

2.初始化中断向量表;

3.复位中断函数(Reset_Handler){系统初始化,然后进入main函数};

4.中断函数的弱(WEAK)声明

5.用户栈和堆初始化

三、启动文件使用的汇编指令汇总

启动文件一般都是由汇编代码和伪指令来写的。

1、下面表格就是启动文件中出现的伪指令名称及其相关的含义。请大家参考:

2、几个名词解释

堆主要用来动态内存的分配,像 malloc()函数申请的内存就在堆上面。这个在 STM32里面用的比较少

栈的作用是用于局部变量,函数调用,函数形参等的开销,栈的大小不能超过内部SRAM的大小。栈的生长方向是由高地址向低地址扩展。

THUMB

THUMB:表示后面指令兼容 THUMB 指令。 THUBM 是 ARM以前的指令集, 16bit,现在 Cortex-M 系列的都使用 THUMB-2 指令集, THUMB-2 是 32 位的,兼容 16 位和 32 位的指令,是 THUMB 的超集。

中断向量表

中断向量表:把系统中所有的中断类型码及其对应的中断向量按一定的规律存放在一个区域内,这个存储区域就叫中断向量表。

四、启动文件解读

下面是我项目工程中的完整启动文件代码。按照以上5个内容分类进行展开。这里只选取我觉得比较关键的部分进行阐述,不会逐字逐句的说明。提示注意一下,汇编文件的注释是通过 “;”来开始的,不是像C语言中,是通过// 或者/***/来进行注释的。“;”在汇编文件中,也就等同于.c文件中的“//”。

1.堆栈空间的定义;

Stack_Size      EQU     0x00000400                AREA    STACK, NOINIT, READWRITE, ALIGN=3Stack_Mem       SPACE   Stack_Size__initial_sp; < h > Heap Configuration;   < o >  Heap Size (in Bytes) < 0x0-0xFFFFFFFF:8 >; < /h >Heap_Size       EQU     0x00000200                AREA    HEAP, NOINIT, READWRITE, ALIGN=3__heap_baseHeap_Mem        SPACE   Heap_Size__heap_limit                PRESERVE8

开辟栈的大小为 0X00000400(1KB),名字为 STACK, NOINIT 即不初始化,可读可写, 8(2^3)字节对齐。

开辟堆的大小为 0X00000200(512 字节),名字为 HEAP, NOINIT 即不初始化,可读可写, 8(2^3)字节对齐。

2.初始化中断向量表;

THUMB; Vector Table Mapped to Address 0 at Reset                AREA    RESET, DATA, READONLY                EXPORT  __Vectors                EXPORT  __Vectors_End                EXPORT  __Vectors_Size__Vectors       DCD     __initial_sp               ; Top of Stack                DCD     Reset_Handler              ; Reset Handler                DCD     NMI_Handler                ; NMI Handler                DCD     HardFault_Handler          ; Hard Fault Handler                DCD     MemManage_Handler          ; MPU Fault Handler                DCD     BusFault_Handler           ; Bus Fault Handler                DCD     UsageFault_Handler         ; Usage Fault Handler                DCD     0                          ; Reserved                DCD     0                          ; Reserved                DCD     0                          ; Reserved                DCD     0                          ; Reserved                DCD     SVC_Handler                ; SVCall Handler                DCD     DebugMon_Handler           ; Debug Monitor Handler                DCD     0                          ; Reserved                DCD     PendSV_Handler             ; PendSV Handler                DCD     SysTick_Handler            ; SysTick Handler                ; External Interrupts                DCD     WWDG_IRQHandler                   ; Window WatchDog                                                        DCD     PVD_IRQHandler                    ; PVD through EXTI Line detection                                        DCD     TAMP_STAMP_IRQHandler             ; Tamper and TimeStamps through the EXTI line                            DCD     RTC_WKUP_IRQHandler               ; RTC Wakeup through the EXTI line                                       DCD     FLASH_IRQHandler                  ; FLASH                                                           DCD     RCC_IRQHandler                    ; RCC                                                             DCD     EXTI0_IRQHandler                  ; EXTI Line0                                                             DCD     EXTI1_IRQHandler                  ; EXTI Line1                                                             DCD     EXTI2_IRQHandler                  ; EXTI Line2                                                             DCD     EXTI3_IRQHandler                  ; EXTI Line3                                                             DCD     EXTI4_IRQHandler                  ; EXTI Line4                                                             DCD     DMA1_Stream0_IRQHandler           ; DMA1 Stream 0                                                   DCD     DMA1_Stream1_IRQHandler           ; DMA1 Stream 1                                                   DCD     DMA1_Stream2_IRQHandler           ; DMA1 Stream 2                                                   DCD     DMA1_Stream3_IRQHandler           ; DMA1 Stream 3                                                   DCD     DMA1_Stream4_IRQHandler           ; DMA1 Stream 4                                                   DCD     DMA1_Stream5_IRQHandler           ; DMA1 Stream 5                                                   DCD     DMA1_Stream6_IRQHandler           ; DMA1 Stream 6                                                   DCD     ADC_IRQHandler                    ; ADC1, ADC2 and ADC3s                                            DCD     CAN1_TX_IRQHandler                ; CAN1 TX                                                                DCD     CAN1_RX0_IRQHandler               ; CAN1 RX0                                                               DCD     CAN1_RX1_IRQHandler               ; CAN1 RX1                                                               DCD     CAN1_SCE_IRQHandler               ; CAN1 SCE                                                               DCD     EXTI9_5_IRQHandler                ; External Line[9:5]s                                                    DCD     TIM1_BRK_TIM9_IRQHandler          ; TIM1 Break and TIM9                                   DCD     TIM1_UP_TIM10_IRQHandler          ; TIM1 Update and TIM10                                 DCD     TIM1_TRG_COM_TIM11_IRQHandler     ; TIM1 Trigger and Commutation and TIM11                DCD     TIM1_CC_IRQHandler                ; TIM1 Capture Compare                                                   DCD     TIM2_IRQHandler                   ; TIM2                                                            DCD     TIM3_IRQHandler                   ; TIM3                                                            DCD     TIM4_IRQHandler                   ; TIM4                                                            DCD     I2C1_EV_IRQHandler                ; I2C1 Event                                                             DCD     I2C1_ER_IRQHandler                ; I2C1 Error                                                             DCD     I2C2_EV_IRQHandler                ; I2C2 Event                                                             DCD     I2C2_ER_IRQHandler                ; I2C2 Error                                                               DCD     SPI1_IRQHandler                   ; SPI1                                                            DCD     SPI2_IRQHandler                   ; SPI2                                                            DCD     USART1_IRQHandler                 ; USART1                                                          DCD     USART2_IRQHandler                 ; USART2                                                          DCD     USART3_IRQHandler                 ; USART3                                                          DCD     EXTI15_10_IRQHandler              ; External Line[15:10]s                                                  DCD     RTC_Alarm_IRQHandler              ; RTC Alarm (A and B) through EXTI Line                                  DCD     OTG_FS_WKUP_IRQHandler            ; USBOTG FS Wakeup through EXTI line                                        DCD     TIM8_BRK_TIM12_IRQHandler         ; TIM8 Break and TIM12                                  DCD     TIM8_UP_TIM13_IRQHandler          ; TIM8 Update and TIM13                                 DCD     TIM8_TRG_COM_TIM14_IRQHandler     ; TIM8 Trigger and Commutation and TIM14                DCD     TIM8_CC_IRQHandler                ; TIM8 Capture Compare                                                   DCD     DMA1_Stream7_IRQHandler           ; DMA1 Stream7                                                           DCD     FSMC_IRQHandler                   ; FSMC                                                            DCD     SDIO_IRQHandler                   ; SDIO                                                            DCD     TIM5_IRQHandler                   ; TIM5                                                            DCD     SPI3_IRQHandler                   ; SPI3                                                            DCD     UART4_IRQHandler                  ; UART4                                                           DCD     UART5_IRQHandler                  ; UART5                                                           DCD     TIM6_DAC_IRQHandler               ; TIM6 and DAC1&2 underrun errorsDCD     TIM7_IRQHandler                   ; TIM7                                   DCD     DMA2_Stream0_IRQHandler           ; DMA2 Stream 0                                                   DCD     DMA2_Stream1_IRQHandler           ; DMA2 Stream 1                                                   DCD     DMA2_Stream2_IRQHandler           ; DMA2 Stream 2                                                   DCD     DMA2_Stream3_IRQHandler           ; DMA2 Stream 3                                                   DCD     DMA2_Stream4_IRQHandler           ; DMA2 Stream 4                                                   DCD     ETH_IRQHandler                    ; EthernetDCD     ETH_WKUP_IRQHandler               ; Ethernet Wakeup through EXTI line                                      DCD     CAN2_TX_IRQHandler                ; CAN2 TX                                                                DCD     CAN2_RX0_IRQHandler               ; CAN2 RX0                                                               DCD     CAN2_RX1_IRQHandler               ; CAN2 RX1                                                               DCD     CAN2_SCE_IRQHandler               ; CAN2 SCE                                                               DCD     OTG_FS_IRQHandler                 ; USB OTG FS                                                      DCD     DMA2_Stream5_IRQHandler           ; DMA2 Stream 5                                                   DCD     DMA2_Stream6_IRQHandler           ; DMA2 Stream 6                                                   DCD     DMA2_Stream7_IRQHandler           ; DMA2 Stream 7                                                   DCD     USART6_IRQHandler                 ; USART6                                                           DCD     I2C3_EV_IRQHandler                ; I2C3 event                                                             DCD     I2C3_ER_IRQHandler                ; I2C3 error                                                             DCD     OTG_HS_EP1_OUT_IRQHandler         ; USB OTG HS End Point 1 Out                                      DCD     OTG_HS_EP1_IN_IRQHandler          ; USB OTG HS End Point 1 In                                       DCD     OTG_HS_WKUP_IRQHandler            ; USB OTG HS Wakeup through EXTI                                         DCD     OTG_HS_IRQHandler                 ; USB OTG HS                                                      DCD     DCMI_IRQHandler                   ; DCMI                                                            DCD     CRYP_IRQHandler                   ; CRYP crypto                                                     DCD     HASH_RNG_IRQHandler               ; Hash and Rng                DCD     FPU_IRQHandler                    ; FPU__Vectors_End__Vectors_Size  EQU  __Vecto- __Vectors

3.复位中断函数(Reset_Handler){系统初始化,然后进入main函数};

AREA    |.text|, CODE, READONLY; Reset handlerReset_Handler    PROC                 EXPORT  Reset_Handler             [WEAK]        IMPORT  SystemInit        IMPORT  __main                 LDR     R0, =SystemInit                 BLX     R0                 LDR     R0, =__main                 BX      R0                 ENDP

4.中断函数的弱(WEAK)声明

; Dummy Exception Handlers (infinite loops which can be modified)NMI_Handler     PROC                EXPORT  NMI_Handler                [WEAK]                B       .                ENDPHardFault_Handler\\                PROC                EXPORT  HardFault_Handler          [WEAK]                B       .                ENDPMemManage_Handler\\                PROC                EXPORT  MemManage_Handler          [WEAK]                B       .                ENDPBusFault_Handler\\                PROC                EXPORT  BusFault_Handler           [WEAK]                B       .                ENDPUsageFault_Handler\\                PROC                EXPORT  UsageFault_Handler         [WEAK]                B       .                ENDPSVC_Handler     PROC                EXPORT  SVC_Handler                [WEAK]                B       .                ENDPDebugMon_Handler\\                PROC                EXPORT  DebugMon_Handler           [WEAK]                B       .                ENDPPendSV_Handler  PROC                EXPORT  PendSV_Handler             [WEAK]                B       .                ENDPSysTick_Handler PROC                EXPORT  SysTick_Handler            [WEAK]                B       .                ENDPDefault_Handler PROC                EXPORT  WWDG_IRQHandler                   [WEAK]                                                        EXPORT  PVD_IRQHandler                    [WEAK]                                      EXPORT  TAMP_STAMP_IRQHandler             [WEAK]                         EXPORT  RTC_WKUP_IRQHandler               [WEAK]                                     EXPORT  FLASH_IRQHandler                  [WEAK]                                                         EXPORT  RCC_IRQHandler                    [WEAK]                                                            EXPORT  EXTI0_IRQHandler                  [WEAK]                                                            EXPORT  EXTI1_IRQHandler                  [WEAK]                                                             EXPORT  EXTI2_IRQHandler                  [WEAK]                                                            EXPORT  EXTI3_IRQHandler                  [WEAK]                                                           EXPORT  EXTI4_IRQHandler                  [WEAK]                                                            EXPORT  DMA1_Stream0_IRQHandler           [WEAK]                                                EXPORT  DMA1_Stream1_IRQHandler           [WEAK]                                                   EXPORT  DMA1_Stream2_IRQHandler           [WEAK]                                                   EXPORT  DMA1_Stream3_IRQHandler           [WEAK]                                                   EXPORT  DMA1_Stream4_IRQHandler           [WEAK]                                                   EXPORT  DMA1_Stream5_IRQHandler           [WEAK]                                                   EXPORT  DMA1_Stream6_IRQHandler           [WEAK]                                                   EXPORT  ADC_IRQHandler                    [WEAK]                                         EXPORT  CAN1_TX_IRQHandler                [WEAK]                                                                EXPORT  CAN1_RX0_IRQHandler               [WEAK]                                                               EXPORT  CAN1_RX1_IRQHandler               [WEAK]                                                                EXPORT  CAN1_SCE_IRQHandler               [WEAK]                                                                EXPORT  EXTI9_5_IRQHandler                [WEAK]                                                    EXPORT  TIM1_BRK_TIM9_IRQHandler          [WEAK]                                  EXPORT  TIM1_UP_TIM10_IRQHandler          [WEAK]                                EXPORT  TIM1_TRG_COM_TIM11_IRQHandler     [WEAK]                 EXPORT  TIM1_CC_IRQHandler                [WEAK]                                                   EXPORT  TIM2_IRQHandler                   [WEAK]                                                            EXPORT  TIM3_IRQHandler                   [WEAK]                                                            EXPORT  TIM4_IRQHandler                   [WEAK]                                                            EXPORT  I2C1_EV_IRQHandler                [WEAK]                                                             EXPORT  I2C1_ER_IRQHandler                [WEAK]                                                             EXPORT  I2C2_EV_IRQHandler                [WEAK]                                                            EXPORT  I2C2_ER_IRQHandler                [WEAK]                                                               EXPORT  SPI1_IRQHandler                   [WEAK]                                                           EXPORT  SPI2_IRQHandler                   [WEAK]                                                            EXPORT  USART1_IRQHandler                 [WEAK]                                                          EXPORT  USART2_IRQHandler                 [WEAK]                                                          EXPORT  USART3_IRQHandler                 [WEAK]                                                         EXPORT  EXTI15_10_IRQHandler              [WEAK]                                                  EXPORT  RTC_Alarm_IRQHandler              [WEAK]                                  EXPORT  OTG_FS_WKUP_IRQHandler            [WEAK]                                        EXPORT  TIM8_BRK_TIM12_IRQHandler         [WEAK]                                 EXPORT  TIM8_UP_TIM13_IRQHandler          [WEAK]                                 EXPORT  TIM8_TRG_COM_TIM14_IRQHandler     [WEAK]                 EXPORT  TIM8_CC_IRQHandler                [WEAK]                                                   EXPORT  DMA1_Stream7_IRQHandler           [WEAK]                                                          EXPORT  FSMC_IRQHandler                   [WEAK]                                                             EXPORT  SDIO_IRQHandler                   [WEAK]                                                             EXPORT  TIM5_IRQHandler                   [WEAK]                                                             EXPORT  SPI3_IRQHandler                   [WEAK]                                                             EXPORT  UART4_IRQHandler                  [WEAK]                                                            EXPORT  UART5_IRQHandler                  [WEAK]                                                            EXPORT  TIM6_DAC_IRQHandler               [WEAK]                                   EXPORT  TIM7_IRQHandler                   [WEAK]                                    EXPORT  DMA2_Stream0_IRQHandler           [WEAK]                                                  EXPORT  DMA2_Stream1_IRQHandler           [WEAK]                                                   EXPORT  DMA2_Stream2_IRQHandler           [WEAK]                                                    EXPORT  DMA2_Stream3_IRQHandler           [WEAK]                                                    EXPORT  DMA2_Stream4_IRQHandler           [WEAK]                                                 EXPORT  ETH_IRQHandler                    [WEAK]                                                         EXPORT  ETH_WKUP_IRQHandler               [WEAK]                                     EXPORT  CAN2_TX_IRQHandler                [WEAK]                                                               EXPORT  CAN2_RX0_IRQHandler               [WEAK]                                                               EXPORT  CAN2_RX1_IRQHandler               [WEAK]                                                               EXPORT  CAN2_SCE_IRQHandler               [WEAK]                                                               EXPORT  OTG_FS_IRQHandler                 [WEAK]                                                       EXPORT  DMA2_Stream5_IRQHandler           [WEAK]                                                   EXPORT  DMA2_Stream6_IRQHandler           [WEAK]                                                   EXPORT  DMA2_Stream7_IRQHandler           [WEAK]                                                   EXPORT  USART6_IRQHandler                 [WEAK]                                                           EXPORT  I2C3_EV_IRQHandler                [WEAK]                                                              EXPORT  I2C3_ER_IRQHandler                [WEAK]                                                              EXPORT  OTG_HS_EP1_OUT_IRQHandler         [WEAK]                                      EXPORT  OTG_HS_EP1_IN_IRQHandler          [WEAK]                                      EXPORT  OTG_HS_WKUP_IRQHandler            [WEAK]                                        EXPORT  OTG_HS_IRQHandler                 [WEAK]                                                      EXPORT  DCMI_IRQHandler                   [WEAK]                                                             EXPORT  CRYP_IRQHandler                   [WEAK]                                                     EXPORT  HASH_RNG_IRQHandler               [WEAK]                EXPORT  FPU_IRQHandler                    [WEAK]WWDG_IRQHandler                                                       PVD_IRQHandler                                      TAMP_STAMP_IRQHandler                  RTC_WKUP_IRQHandler                                FLASH_IRQHandler                                                       RCC_IRQHandler                                                            EXTI0_IRQHandler                                                          EXTI1_IRQHandler                                                           EXTI2_IRQHandler                                                          EXTI3_IRQHandler                                                         EXTI4_IRQHandler                                                          DMA1_Stream0_IRQHandler                                       DMA1_Stream1_IRQHandler                                          DMA1_Stream2_IRQHandler                                          DMA1_Stream3_IRQHandler                                          DMA1_Stream4_IRQHandler                                          DMA1_Stream5_IRQHandler                                          DMA1_Stream6_IRQHandler                                          ADC_IRQHandler                                         CAN1_TX_IRQHandler                                                            CAN1_RX0_IRQHandler                                                          CAN1_RX1_IRQHandler                                                           CAN1_SCE_IRQHandler                                                           EXTI9_5_IRQHandler                                                TIM1_BRK_TIM9_IRQHandler                        TIM1_UP_TIM10_IRQHandler                      TIM1_TRG_COM_TIM11_IRQHandler  TIM1_CC_IRQHandler                                               TIM2_IRQHandler                                                           TIM3_IRQHandler                                                           TIM4_IRQHandler                                                           I2C1_EV_IRQHandler                                                         I2C1_ER_IRQHandler                                                         I2C2_EV_IRQHandler                                                        I2C2_ER_IRQHandler                                                           SPI1_IRQHandler                                                          SPI2_IRQHandler                                                           USART1_IRQHandler                                                       USART2_IRQHandler                                                       USART3_IRQHandler                                                      EXTI15_10_IRQHandler                                            RTC_Alarm_IRQHandler                            OTG_FS_WKUP_IRQHandler                                TIM8_BRK_TIM12_IRQHandler                      TIM8_UP_TIM13_IRQHandler                       TIM8_TRG_COM_TIM14_IRQHandler  TIM8_CC_IRQHandler                                               DMA1_Stream7_IRQHandler                                                 FSMC_IRQHandler                                                            SDIO_IRQHandler                                                            TIM5_IRQHandler                                                            SPI3_IRQHandler                                                            UART4_IRQHandler                                                          UART5_IRQHandler                                                          TIM6_DAC_IRQHandler                            TIM7_IRQHandler                              DMA2_Stream0_IRQHandler                                         DMA2_Stream1_IRQHandler                                          DMA2_Stream2_IRQHandler                                           DMA2_Stream3_IRQHandler                                           DMA2_Stream4_IRQHandler                                        ETH_IRQHandler                                                         ETH_WKUP_IRQHandler                                CAN2_TX_IRQHandler                                                           CAN2_RX0_IRQHandler                                                          CAN2_RX1_IRQHandler                                                          CAN2_SCE_IRQHandler                                                          OTG_FS_IRQHandler                                                    DMA2_Stream5_IRQHandler                                          DMA2_Stream6_IRQHandler                                          DMA2_Stream7_IRQHandler                                          USART6_IRQHandler                                                        I2C3_EV_IRQHandler                                                          I2C3_ER_IRQHandler                                                          OTG_HS_EP1_OUT_IRQHandler                           OTG_HS_EP1_IN_IRQHandler                            OTG_HS_WKUP_IRQHandler                                OTG_HS_IRQHandler                                                   DCMI_IRQHandler                                                            CRYP_IRQHandler                                                    HASH_RNG_IRQHandlerFPU_IRQHandler                B       .                ENDP                ALIGN

如果我们在使用某个外设的时候,开启了某个中断,但是又忘记编写配套的中断服务程序或者函数名写错,那当中断来临的时,程序就会跳转到启动文件预先写好的空的中断服务程序中,并且在这个空函数中无线循环,即程序就死在这里。这也是[weak]起到的作用。关于weak,可以网络搜索,了解一下虚函数,和这里是一个意思。

5.用户栈和堆初始化

;*******************************************************************************; User Stack and Heap initialization;*******************************************************************************                 IF      :DEF:__MICROLIB                 EXPORT  __initial_sp                 EXPORT  __heap_base                 EXPORT  __heap_limit                 ELSE                 IMPORT  __use_two_region_memory                 EXPORT  __user_initial_stackheap__user_initial_stackheap                 LDR     R0, =  Heap_Mem                 LDR     R1, =(Stack_Mem + Stack_Size)                 LDR     R2, = (Heap_Mem +  Heap_Size)                 LDR     R3, = Stack_Mem                 BX      LR                 ALIGN                 ENDIF                 END

五、理解启动文件的用途总结

1、项目整体把控

每一款芯片,如果你想使用它来做开发,那都有必要了解一下它的启动文件。通过了解,我们可以体会到处理器的架构、指令集、中断向量安排等内容,对整个片子有一个整体的认识。

2、修改堆栈

如果堆栈不够用了,可以修改他们的大小。尤其是栈,当我们需求增加,代码量自然而然就会增多。那么定义的局部变量,函数嵌套的层数必然也就会增多。这个时候就需要关注栈的大小,如果发生溢出,程序就会发生意想不到的后果。

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