STM32F0系列MCU中断向量表的重映射

最近使⽤了⼀款Cortex-M0内核的芯⽚STM32F030CC，发现它中断向量表的重映射⽅法与STM32F10x系列的有所区别，在这⾥记录与分享⼀下。

由于需要通过IAP进⾏固件升级，所以芯⽚的FLASH⾥⾯要烧录两份代码：⼀个Boot loader, ⼀个⽤户应⽤程序。理所当然的，在⽤户应⽤程序中，必须得重新映射中断向量表。

可是在ST提供的固件库⾥，我却没有发现类似于stm32f10x固件库中的void NVIC_SetVectorTable(uint32_t NVIC_VectTab, uint32_tOffset)接⼝。

浏览了⼀下,原来M0并没有SCB->VTOR这个寄存器，难怪ST的库⾥没有提供NVIC_SetVectorTable这个接⼝。 这下要怎么办？在⽹络上搜索了⼀下，受到⽹友的启发，我在中找到以下说明： Physical remap

　　Once the boot mode is selected, the application software can modify the memory accessible in the code area.This modification is

performed by programming the MEM_MODE bits in the SYSCFG configuration register 1 (SYSCFG_CFGR1). Unlike Cortex® M3 and M4,the M0 CPU does not support the vector table relocation. For application code which is located in a different address than 0x0800 0000,some additional code must be added in order to be able to serve the application interrupts. A solution will be to relocate by software thevector table to the internal SRAM:

　　• Copy the vector table from the Flash (mapped at the base of the application load address) to the base address of the SRAM at0x2000 0000.

　　• Remap SRAM at address 0x0000 0000, using SYSCFG configuration register 1.

　　• Then once an interrupt occurs, the Cortex®-M0 processor will fetch the interrupt handler start address from the relocated vector tablein SRAM, then it will jump to execute the interrupt handler located in the Flash.

　　This operation should be done at the initialization phase of the application. Please refer to and attached IAP code from for moredetails.

　　OK,解决⽅法找到了！　　

　　在⽤户应⽤程序中，按照以上⽅法，添加以下两⾏代码：

memcpy((void*)0x20000000, (void*)0x08004000, VECTOR_SIZE); SYSCFG_MemoryRemapConfig(SYSCFG_MemoryRemap_SRAM);

　　 其中，0x2000 0000是SRAM的起始地址，这个不需要改动。

　　 ⽽之后的两个参数需要根据实际情况作出修改。0x0800 4000是应⽤程序的起址地址，从这⾥开始的VECTOR_SIZE字节，存放是的应⽤程序的中断向量表。VECTOR_SIZE是指中断向量表的⼤⼩，具体多⼤可以在startup.s⽂件⾥计算得到。以下以startup_stm32f030.s为例作说明：

1 Stack_Size EQU 0x00000400 2

3 AREA STACK, NOINIT, READWRITE, ALIGN=3 4 Stack_Mem SPACE Stack_Size 5 __initial_sp 6 7

8 ; Heap Configuration

9 ; Heap Size (in Bytes) <0x0-0xFFFFFFFF:8> 10 ; 11

12 Heap_Size EQU 0x00000200 13

14 AREA HEAP, NOINIT, READWRITE, ALIGN=3 15 __heap_base

16 Heap_Mem SPACE Heap_Size 17 __heap_limit 18

19 PRESERVE8 20 THUMB 21 22

23 ; Vector Table Mapped to Address 0 at Reset 24 AREA RESET, DATA, READONLY 25 EXPORT __Vectors

26 EXPORT __Vectors_End 27 EXPORT __Vectors_Size 28

29 __Vectors DCD __initial_sp ; Top of Stack 30 DCD Reset_Handler ; Reset Handler 31 DCD NMI_Handler ; NMI Handler

32 DCD HardFault_Handler ; Hard Fault Handler 33 DCD 0 ; Reserved 34 DCD 0 ; Reserved 35 DCD 0 ; Reserved 36 DCD 0 ; Reserved 37 DCD 0 ; Reserved 38 DCD 0 ; Reserved 39 DCD 0 ; Reserved

40 DCD SVC_Handler ; SVCall Handler 41 DCD 0 ; Reserved 42 DCD 0 ; Reserved

43 DCD PendSV_Handler ; PendSV Handler 44 DCD SysTick_Handler ; SysTick Handler 45

46 ; External Interrupts

47 DCD WWDG_IRQHandler ; Window Watchdog 48 DCD 0 ; Reserved

49 DCD RTC_IRQHandler ; RTC through EXTI Line 50 DCD FLASH_IRQHandler ; FLASH 51 DCD RCC_IRQHandler ; RCC

52 DCD EXTI0_1_IRQHandler ; EXTI Line 0 and 1 53 DCD EXTI2_3_IRQHandler ; EXTI Line 2 and 3 DCD EXTI4_15_IRQHandler ; EXTI Line 4 to 15 55 DCD 0 ; Reserved

56 DCD DMA1_Channel1_IRQHandler ; DMA1 Channel 1

57 DCD DMA1_Channel2_3_IRQHandler ; DMA1 Channel 2 and Channel 3 58 DCD DMA1_Channel4_5_IRQHandler ; DMA1 Channel 4 and Channel 5 59 DCD ADC1_IRQHandler ; ADC1

60 DCD TIM1_BRK_UP_TRG_COM_IRQHandler ; TIM1 Break, Update, Trigger and Commutation 61 DCD TIM1_CC_IRQHandler ; TIM1 Capture Compare 62 DCD 0 ; Reserved 63 DCD TIM3_IRQHandler ; TIM3 DCD 0 ; Reserved 65 DCD 0 ; Reserved 66 DCD TIM14_IRQHandler ; TIM14 67 DCD TIM15_IRQHandler ; TIM15 68 DCD TIM16_IRQHandler ; TIM16 69 DCD TIM17_IRQHandler ; TIM17 70 DCD I2C1_IRQHandler ; I2C1 71 DCD I2C2_IRQHandler ; I2C2 72 DCD SPI1_IRQHandler ; SPI1 73 DCD SPI2_IRQHandler ; SPI2

74 DCD USART1_IRQHandler ; USART1 75 DCD USART2_IRQHandler ; USART2 76 77 __Vectors_End 78

79 __Vectors_Size EQU __Vectors_End - __Vectors 80

81 AREA |.text|, CODE, READONLY 82

83 ; Reset handler routine 84 Reset_Handler PROC

85 EXPORT Reset_Handler [WEAK] 86 IMPORT __main 87 IMPORT SystemInit 88 90

91 LDR R0, =__initial_sp ; set stack pointer 92 MSR MSP, R0 93

　　我们只需关注其中的⼀⼩部分。从29⾏开始，直到75⾏，每⼀个DCD都代表⼀个中断向量（所谓中断向量，说得明⽩点，其实就是某个中断服务程序的⼊⼝地址）。例如第74⾏的：

　　DCD USART1_IRQHandler ; USART1

　　这⾥的“USART1_IRQHandler\"其实就是UART1中断服务程序USART1_IRQHandler这个函数，同时，它也代表这个函数的⼊⼝地址。　　以上代码即定义了这样⼀张表，这张表包括45个元素，每个元素是⼀个长度为4字节的地址。除了第⼀个地址是SP（堆栈指针）外，其它的地址都是某个中断服务程序的⼊⼝地址。

　　那么，回到我们要解决的问题上来，之前memcpy函数中的第三个参数VECTOR_SIZE，针对本例，就应该是45*4=180（0xB4）个字节。

　　在执⾏完以上两⾏代码后，若发⽣中断，CPU就会去SRAM（即0x2000 0000处）取中断向量了，所以，以0x2000 0000作为起始地址之后的VECTOR_SIZE个字节就不能被改动了。为了达到这VECTOR_SIZE个字节不被修改的⽬的，如下两种⽅法可以实现。　　•在⼯程⽂件内修改SRAM的起始地址及长度，如下图

　　•如果使⽤了分散加载⽂件，则在分散加载⽂件中修改SRAM的起始地址及长度也能达到⽬的。　　

　　⾄此，STM32F0系列Cortex-M0内核芯⽚中断向量表重映射的问题已解决。