1.Keil中的定义方法
在Keil中可以使用分散加载文件来实现，代码标记了EE_FLASH的ROM放置区段和CCMRAM的区段
LR_IROM1 0x08000000 0x00080000 { ; load region size_region
ER_IROM1 0x08000000 0x00080000 { ; load address = execution address
*.o (RESET, +First)
*(InRoot$$Sections)
.ANY (+RO)
}
ER_IROM2 0x08040000 FIXED{
*.o(EE_FLASH)
}
RW_IRAM1 0x20000000 0x00020000 { ; RW data
.ANY (+RW +ZI)
}
; RW_IRAM2 0x10000000 0x00010000 {
; .ANY (ccmram)
; }
ER 0x10000000 0x00010000{
.ANY (ccmram)
}
}
使用特定ROM的方法：
u16 __attribute__ ((section ("EE_FLASH"))) Read_Encryption(void)
{
}使用特定RAM的方法：
#define CCMRAM __attribute__((section("ccmram"))) //使用ccm内存 内核高速内存 无法dma 可以定义函数在这个区域
CCMRAM volatile u16 udp_port;绝对地址放置方法：
const u16 hd_arm_id[3] __attribute__((at(0x08003400))) = {0xFFFF,0xFFFF,0xFFFF}; 2.GCC中的定义方法
修改ld文件来加入定义区段
ENTRY(Reset_Handler)
/* Highest address of the user mode stack */
_estack = 0x20020000; /* end of RAM */
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0x200; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */
/* Specify the memory areas */
MEMORY
{
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
CCMRAM (xrw) : ORIGIN = 0x10000000, LENGTH = 64K
BACKRAM (xrw) :ORIGIN = 0x40024000, LENGTH = 4
FLASH (rx) : ORIGIN = 0x8020000, LENGTH = 128K*3
SCRIPT_FLASH (rx) : ORIGIN = 0x8010000, LENGTH = 64K
}
_Privileged_Functions_Region_Size = 16K;
_Privileged_Data_Region_Size = 256;
__FLASH_segment_start__ = ORIGIN( FLASH );
__FLASH_segment_end__ = __FLASH_segment_start__ + LENGTH( FLASH );
__privileged_functions_start__ = ORIGIN( FLASH );
__privileged_functions_end__ = __privileged_functions_start__ + _Privileged_Functions_Region_Size;
__SRAM_segment_start__ = ORIGIN( RAM );
__SRAM_segment_end__ = __SRAM_segment_start__ + LENGTH( RAM );
__privileged_data_start__ = ORIGIN( RAM );
__privileged_data_end__ = ORIGIN( RAM ) + _Privileged_Data_Region_Size;
/* Define output sections */
SECTIONS
{
/* The startup code goes first into FLASH */
.isr_vector :
{
. = ALIGN(4);
KEEP(*(.isr_vector)) /* Startup code */
. = ALIGN(4);
} >FLASH
/* The program code and other data goes into FLASH */
.text :
{
. = ALIGN(4);
*(.text) /* .text sections (code) */
*(.text*) /* .text* sections (code) */
*(.glue_7) /* glue arm to thumb code */
*(.glue_7t) /* glue thumb to arm code */
*(.eh_frame)
KEEP (*(.init))
KEEP (*(.fini))
. = ALIGN(4);
_etext = .; /* define a global symbols at end of code */
} >FLASH
/* Constant data goes into FLASH */
.rodata :
{
. = ALIGN(4);
*(.rodata) /* .rodata sections (constants, strings, etc.) */
*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >FLASH
.ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
.ARM : {
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
} >FLASH
.preinit_array :
{
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array*))
PROVIDE_HIDDEN (__preinit_array_end = .);
} >FLASH
.init_array :
{
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array*))
PROVIDE_HIDDEN (__init_array_end = .);
} >FLASH
.fini_array :
{
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT(.fini_array.*)))
KEEP (*(.fini_array*))
PROVIDE_HIDDEN (__fini_array_end = .);
} >FLASH
.script_flash_table :
{
. = ALIGN(4);
*(.script_flash_table) /* .rodata sections (constants, strings, etc.) */
*(.script_flash_table*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >SCRIPT_FLASH
/* used by the startup to initialize data */
_sidata = LOADADDR(.data);
/* Initialized data sections goes into RAM, load LMA copy after code */
.data :
{
. = ALIGN(4);
_sdata = .; /* create a global symbol at data start */
*(.data) /* .data sections */
*(.data*) /* .data* sections */
. = ALIGN(4);
_edata = .; /* define a global symbol at data end */
} >RAM AT> FLASH
_siccmram = LOADADDR(.ccmram);
/* CCM-RAM section
*
* IMPORTANT NOTE!
* If initialized variables will be placed in this section,
* the startup code needs to be modified to copy the init-values.
*/
.ccmram :
{
. = ALIGN(4);
_sccmram = .; /* create a global symbol at ccmram start */
*(.ccmram)
*(.ccmram*)
. = ALIGN(4);
_eccmram = .; /* create a global symbol at ccmram end */
} >CCMRAM AT> FLASH
.backram :
{
. = ALIGN(4);
_sbackram = .; /* create a global symbol at ccmram start */
*(.backram)
*(.backram*)
. = ALIGN(4);
_ebackram = .; /* create a global symbol at ccmram end */
} >BACKRAM AT> FLASH
/* Uninitialized data section */
. = ALIGN(4);
.bss :
{
/* This is used by the startup in order to initialize the .bss secion */
_sbss = .; /* define a global symbol at bss start */
__bss_start__ = _sbss;
*(.bss)
*(.bss*)
*(COMMON)
. = ALIGN(4);
_ebss = .; /* define a global symbol at bss end */
__bss_end__ = _ebss;
} >RAM
/* User_heap_stack section, used to check that there is enough RAM left */
._user_heap_stack :
{
. = ALIGN(8);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(8);
} >RAM
/* Remove information from the standard libraries */
/DISCARD/ :
{
libc.a ( * )
libm.a ( * )
libgcc.a ( * )
}
.ARM.attributes 0 : { *(.ARM.attributes) }
}使用方法：
#define USE_CCMRAM __attribute__((section(".ccmram")))
#define USE_BACKRAM __attribute__((section(".backram")))
#define USE_SCRIPT_FLASH __attribute__((section(".script_flash_table")))
USE_CCMRAM StepMotorRunStruct Motor_Run[MOTOR_NUB];需要注意的是CCMRAM在.s文件中并不会初始化，如果需要该处的RAM初始化，需要在.s文件中添加初始化为0，或者将FLASH搬运至CCMRAM的指令
CopyCCMRAMInit:
ldr r3, =_siccmram
ldr r3, [r3, r1]
str r3, [r0, r1]
adds r1, r1, #4
LoopCopyCCMRAMInit:
ldr r0, =_sccmram
ldr r3, =_eccmram
adds r2, r0, r1
cmp r2, r3
bcc CopyCCMRAMInit