使用Keil将STM32部分程序放在RAM中运行

手动分配RAM区域,新建.sct文件,定义RAM_CODE区域,并指定其正确的起始地址和大小。

; *************************************************************
; *** Scatter-Loading Description File generated by uVision ***
; *************************************************************

LR_IROM1 0x08000000 0x00010000  {    ; load region size_region
  ER_IROM1 0x08000000 0x00010000  {  ; load address = execution address
   *.o (RESET, +First)
   *(InRoot$$Sections)
   .ANY (+RO)
   .ANY (+XO)
  }
  RW_IRAM1 0x20000000 0x4000  {  ; RW data in RAM 
   .ANY (+RW +ZI)
  }
  ER_RAM_CODE 0x20004000 0x1000 {  ; Execution region in RAM for specific functions
    *.o (.RAM_CODE)
  }
}

在keil中,打开“Options for Target”，选择“Linker”选项卡，手动选择新生成的.sct文件在这里插入图片描述
2. 手动标记函数：
在函数定义中使用 attribute((section(“.RAM_CODE”))) 明确标记需要放置在RAM中的函数。

__attribute__((section(".RAM_CODE")))
void SPI1_Nss_High(void)
{
    HAL_GPIO_WritePin(SPI1_NSS_GPIO_Port, SPI1_NSS_Pin, GPIO_PIN_SET);
}

__attribute__((section(".RAM_CODE")))
void HAL_GPIO_WritePin(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin, GPIO_PinState PinState)
{
  /* Check the parameters */
  assert_param(IS_GPIO_PIN(GPIO_Pin));
  assert_param(IS_GPIO_PIN_ACTION(PinState));

  if (PinState != GPIO_PIN_RESET)
  {
    GPIOx->BSRR = GPIO_Pin;
  }
  else
  {
    GPIOx->BSRR = (uint32_t)GPIO_Pin << 16u;
  }
}

3.修改启动文件,将指定代码从Flash搬运到RAM:

//修改前.s启动代码
; Reset handler
Reset_Handler    PROC
                 EXPORT  Reset_Handler             [WEAK]
     IMPORT  __main
     IMPORT  SystemInit
                 LDR     R0, =SystemInit
                 BLX     R0
                 LDR     R0, =__main
                 BX      R0
                 ENDP

//修改后启动代码(cortex-M3)
RAM_CODE_START    EQU 0x20004000  ; RAM????????
RAM_CODE_SIZE     EQU 0x1000      ; RAM??????
FLASH_CODE_START  EQU 0x08000000
; Reset handler
Reset_Handler    PROC
                 EXPORT  Reset_Handler             [WEAK]
     IMPORT  __main
     IMPORT  SystemInit
                                 LDR     R0, =SystemInit
                BLX     R0

                ; Copy RAM code section from Flash to RAM
                LDR     R1, =FLASH_CODE_START
                LDR     R2, =RAM_CODE_START
                LDR     R3, =RAM_CODE_SIZE
Copy_RAM_Code
                LDRB    R0, [R1], #1
                STRB    R0, [R2], #1
                SUBS    R3, R3, #1
                BNE     Copy_RAM_Code

                ; Enter the C runtime environment
                 LDR     R0, =__main
                 BX      R0
                 ENDP

如果单片机内核是cortex-m0+,修改后代码如下

//修改后启动代码(cortex-M0+)
RAM_CODE_START    EQU 0x20006000  ; RAM????????
RAM_CODE_SIZE     EQU 0x1000      ; RAM??????
FLASH_CODE_START  EQU 0x00000000
; Reset handler
Reset_Handler    PROC
                 EXPORT  Reset_Handler             [WEAK]
     IMPORT  __main
     IMPORT  SystemInit
                                 LDR     R0, =SystemInit
                BLX     R0

                ; Copy RAM code section from Flash to RAM
                LDR     R1, =FLASH_CODE_START
                LDR     R2, =RAM_CODE_START
                LDR     R3, =RAM_CODE_SIZE
Copy_RAM_Code
                LDRB    R0, [R1]
                STRB    R0, [R2]
                ADDS    R1, R1, #1
                ADDS    R2, R2, #1
                SUBS    R3, R3, #1
                BNE     Copy_RAM_Code

                ; Enter the C runtime environment
                LDR     R0, =__main
                BX      R0
                ENDP