S32K312 DTCM在代码中使用示例

        TCM是一种被直接集成在CPU芯片中的高速缓存,TCM又分为ITCM(Instruction TCM)和DTCM(Data TCM)。ITCM是用来存储代码段的,DTCM是用来存储数据的。

        为什么要使用DTCM来存储数据?1)频繁存取的数据,放到DTCM中以节省存取时间;2)存放到DTCM的数据,不会占用RAM的空间。

        在S32 Design Studio for S32 Platform 3.4的IDE中,如何编写代码,能够成功使用这个空间,示例代码:

/*==================================================================================================
*   Project              : RTD AUTOSAR 4.4
*   Platform             : CORTEXM
*   Peripheral           : S32K3XX
*   Dependencies         : none
*
*   Autosar Version      : 4.4.0
*   Autosar Revision     : ASR_REL_4_4_REV_0000
*   Autosar Conf.Variant :
*   SW Version           : 2.0.1
*   Build Version        : S32K3_RTD_2_0_1_D2207_ASR_REL_4_4_REV_0000_20220707
*
*   (c) Copyright 2020 - 2021 NXP Semiconductors
*   All Rights Reserved.
*
*   NXP Confidential. This software is owned or controlled by NXP and may only be
*   used strictly in accordance with the applicable license terms. By expressly
*   accepting such terms or by downloading, installing, activating and/or otherwise
*   using the software, you are agreeing that you have read, and that you agree to
*   comply with and are bound by, such license terms. If you do not agree to be
*   bound by the applicable license terms, then you may not retain, install,
*   activate or otherwise use the software.
==================================================================================================*/

/**
*   @file main.c
*
*   @addtogroup main_module main module documentation
*   @{
*/

/* Including necessary configuration files. */
#include "Mcal.h"

volatile int exit_code = 0;
/* User includes */

void TestDelay(uint32 delay);
void __attribute__ ((section(".itcm0_code"))) Test_function_in_ITCM(void);


void TestDelay(uint32 delay)
{
    static volatile uint32 DelayTimer = 0;
    while(DelayTimer

当然,上面的只是一部分示例代码,如果不进行其他文件的配置,是不能成功使用的。需要编辑2个配置文件,分别是startup_cm7.s和linker_flash_s32k344.ld,这两个配置文件配置正确,就可以正常使用DTCM了。

linker_flash_s32k344.ld文件编辑注意事项如图红框所示:

S32K312 DTCM在代码中使用示例_第1张图片

linker_flash_s32k344.ld原始文件供参考:

/*==================================================================================================
*   Project              : RTD AUTOSAR 4.4
*   Platform             : CORTEXM
*   Peripheral           : 
*   Dependencies         : none
*
*   Autosar Version      : 4.4.0
*   Autosar Revision     : ASR_REL_4_4_REV_0000
*   Autosar Conf.Variant :
*   SW Version           : 2.0.1
*   Build Version        : S32K3_RTD_2_0_1_D2207_ASR_REL_4_4_REV_0000_20220707
*
*   (c) Copyright 2020 - 2022 NXP Semiconductors
*   All Rights Reserved.
*
*   NXP Confidential. This software is owned or controlled by NXP and may only be
*   used strictly in accordance with the applicable license terms. By expressly
*   accepting such terms or by downloading, installing, activating and/or otherwise
*   using the software, you are agreeing that you have read, and that you agree to
*   comply with and are bound by, such license terms. If you do not agree to be
*   bound by the applicable license terms, then you may not retain, install,
*   activate or otherwise use the software.
==================================================================================================*/
/*
* GCC Linker Command File:
* 0x00400000    0x001F3FFF  2047999 Program Flash (last 64K sBAF)
* 0x10000000    0x1003FFFF  262144  Data Flash (last 32K HSE_NVM)
* 0x20400000    0x20408000  32768   Standby RAM_0 (32K)
* 0x20400000    0x20417FFF  98304   SRAM_0 (96KB)
* Last 48 KB of SRAM_1 reserved by HSE Firmware
* Last 176 KB of CODE_FLASH_3 reserved by HSE Firmware
* Last 128 KB of DATA_FLASH reserved by HSE Firmware (not supported in this linker file)
*/
HEAP_SIZE  = DEFINED(__heap_size__)  ? __heap_size__  : 0x00002000;

ENTRY(Reset_Handler)

MEMORY 
{         
    int_flash               : ORIGIN = 0x00400000, LENGTH = 0x001D4000    /* 2048K - 176K (sBAF + HSE)*/
    int_itcm                : ORIGIN = 0x00000000, LENGTH = 0x00008000    /* 32K */
    int_dtcm                : ORIGIN = 0x20000000, LENGTH = 0x00010000    /* 64K */
    int_sram                : ORIGIN = 0x20400000, LENGTH = 0x00006F00    /* 27 KB */
    int_sram_fls_rsv        : ORIGIN = 0x20406F00, LENGTH = 0x00000100    
    int_sram_stack_c0       : ORIGIN = 0x20407000, LENGTH = 0x00001000    
    int_sram_no_cacheable   : ORIGIN = 0x20408000, LENGTH = 0x00007F00    /* 32kb , needs to include int_results  */
    int_sram_results        : ORIGIN = 0x2040FF00, LENGTH = 0x00000100    
    int_sram_shareable      : ORIGIN = 0x20410000, LENGTH = 0x00008000    /* 32KB */
    ram_rsvd2               : ORIGIN = 0x20418000, LENGTH = 0             /* End of SRAM */
}


SECTIONS
{
    
    .flash :
    {
    	KEEP(*(.boot_header))
        . = ALIGN(4096);
        __text_start = .;
        __interrupts_rom_start = .;
        KEEP(*(.intc_vector))    
        . = ALIGN(4);
        __interrupts_rom_end = .;
        KEEP(*(.core_loop)) 
        . = ALIGN(4);
        *(.startup) 
        . = ALIGN(4);
        *(.systeminit) 
        . = ALIGN(4);
        *(.text.startup) 
        . = ALIGN(4);
        *(.text)
        *(.text*) 
        . = ALIGN(4);
        *(.mcal_text) 
        . = ALIGN(4);
        *(.acmcu_code_rom)
        . = ALIGN(4);
        __acfls_code_rom_start = .;
        *(.acfls_code_rom) 
        . = ALIGN(4);
        __acfls_code_rom_end = .;
        KEEP(*(.init))
        . = ALIGN(4);
        KEEP(*(.fini)) 
         
        . = ALIGN(4);
        *(.rodata)  
        *(.rodata*)  
        . = ALIGN(4);
        *(.mcal_const_cfg)  
        . = ALIGN(4);
        *(.mcal_const)  
        . = ALIGN(4);
        __init_table = .;
        KEEP(*(.init_table))  
        . = ALIGN(4);
        __zero_table = .;
        KEEP(*(.zero_table))
    } > int_flash

    . = ALIGN(4);
    __text_end = .;
    __sram_data_rom = __text_end;
    
    .sram_data : AT(__sram_data_rom)
    {
        . = ALIGN(4);
        __sram_data_begin__ = .;
        . = ALIGN(4);
        *(.ramcode)    
        . = ALIGN(4);
        *(.data)  
        *(.data*)
        . = ALIGN(4);
        *(.mcal_data)
        . = ALIGN(4);
        __sram_data_end__ = .;
    } > int_sram

    __sram_data_rom_end = __sram_data_rom + (__sram_data_end__ - __sram_data_begin__);
    .sram_bss (NOLOAD) :
    {
        . = ALIGN(16);
        __sram_bss_start = .;
        *(.bss)
        *(.bss*)
        . = ALIGN(16);
        *(.mcal_bss)
        . = ALIGN(4);
        __sram_bss_end = .;
    } > int_sram
    /* heap section */        
    .heap (NOLOAD):
    {
    	. += ALIGN(4);
	    _end = .;
	    end = .;
        _heap_start = .;
        . += HEAP_SIZE;
        _heap_end = .;
    } > int_sram
    
    
    .acfls_code_ram :
    {
        acfls_code_ram_start  = .;
        *(.acfls_code_ram)
        acfls_code_ram_stop   = .;
    } > int_sram_fls_rsv

    __non_cacheable_data_rom = __sram_data_rom_end;

    .non_cacheable_data : AT(__non_cacheable_data_rom)
    {
        . = ALIGN(4);
        __non_cacheable_data_start__ = .;
        . = ALIGN(4096);
        __interrupts_ram_start = .;
        . += __interrupts_rom_end - __interrupts_rom_start;    
        . = ALIGN(4);
        __interrupts_ram_end = .;
        *(.mcal_data_no_cacheable)        
        . = ALIGN(4);
        *(.mcal_const_no_cacheable)      
        . = ALIGN(4);
        HSE_LOOP_ADDR = .;
        LONG(0x0);
        __non_cacheable_data_end__ = .;  
    } > int_sram_no_cacheable

	int_results (NOLOAD):
	{
		. = ALIGN(4);
        KEEP(*(.int_results))  
        . += 0x100;
	} > int_sram_results
    
    __non_cacheable_data_rom_end = __non_cacheable_data_rom + (__non_cacheable_data_end__ - __non_cacheable_data_start__);

    .non_cacheable_bss (NOLOAD) :
    {  
        . = ALIGN(16);
        __non_cacheable_bss_start = .;
        *(.mcal_bss_no_cacheable)      
        . = ALIGN(4);
        __non_cacheable_bss_end = .;       
    } > int_sram_no_cacheable
    
    __shareable_data_rom = __non_cacheable_data_rom_end;

    .shareable_data : AT(__shareable_data_rom)
    {
        . = ALIGN(4);
        __shareable_data_start__ = .;
        KEEP(*(.mcal_shared_data)) 
        . = ALIGN(4);
        __shareable_data_end__ = .;  
    } > int_sram_shareable

    __shareable_data_rom_end = __shareable_data_rom + (__shareable_data_end__ - __shareable_data_start__);

    .shareable_bss (NOLOAD) :
    {  
        . = ALIGN(16);
        __shareable_bss_start = .;
        *(.mcal_shared_bss)      
        . = ALIGN(4);
        __shareable_bss_end = .;       
    } > int_sram_shareable
    
    __itcm0_code_rom = __shareable_data_rom_end;

    .itcm0_code : AT(__itcm0_code_rom)
    {
        . = ALIGN(4);
        __itcm0_code_start__ = .;
        KEEP(*(.itcm0_code)) 
        . = ALIGN(4);
        __itcm0_code_end__ = .;  
    } > int_itcm

    __itcm0_code_rom_end = __itcm0_code_rom + (__itcm0_code_end__ - __itcm0_code_start__);
    
    __dtcm0_data_rom = __itcm0_code_rom_end;

    .dtcm0_data : AT(__dtcm0_data_rom)
    {
        . = ALIGN(4);
        __dtcm0_data_start__ = .;
        KEEP(*(.dtcm0_data)) 
        . = ALIGN(4);
        __dtcm0_data_end__ = .;  
    } > int_dtcm

    __dtcm0_data_rom_end = __dtcm0_data_rom + (__dtcm0_data_end__ - __dtcm0_data_start__);

    __Stack_end_c0           = ORIGIN(int_sram_stack_c0);
    __Stack_start_c0         = ORIGIN(int_sram_stack_c0) + LENGTH(int_sram_stack_c0);
    __Stack_end_c1           = 0;
    __Stack_start_c1         = 0;

    __INT_SRAM_START         = ORIGIN(int_sram);
    __INT_SRAM_END           = ORIGIN(ram_rsvd2);
    
    __INT_ITCM_START         = ORIGIN(int_itcm);
    __INT_ITCM_END           = ORIGIN(int_itcm) + LENGTH(int_itcm);
    
    __INT_DTCM_START         = ORIGIN(int_dtcm);
    __INT_DTCM_END           = ORIGIN(int_dtcm) + LENGTH(int_dtcm);
    
    __RAM_SHAREABLE_START    = ORIGIN(int_sram_shareable);
    __RAM_SHAREABLE_END      = ORIGIN(ram_rsvd2)-1;
    __RAM_SHAREABLE_SIZE     = 0xF;
    __ROM_SHAREABLE_START    = __shareable_data_rom;
    __ROM_SHAREABLE_END      = __shareable_data_rom_end;
    __RAM_NO_CACHEABLE_START = ORIGIN(int_sram_no_cacheable);
    __RAM_NO_CACHEABLE_END   = ORIGIN(int_sram_shareable)-1;
    __RAM_NO_CACHEABLE_SIZE  = 0xF;  /* 32kbyte in power of 2 */
    __ROM_NO_CACHEABLE_START = __non_cacheable_data_rom;
    __ROM_NO_CACHEABLE_END   = __non_cacheable_data_rom_end;
    __RAM_CACHEABLE_START    = ORIGIN(int_sram);
    __RAM_CACHEABLE_END      = ORIGIN(int_sram_no_cacheable)-1;
    __RAM_CACHEABLE_SIZE     = 0xF;  /* 32kbyte in power of 2 */
    __ROM_CACHEABLE_START    = __sram_data_rom;
    __ROM_CACHEABLE_END      = __sram_data_rom_end;
    __ROM_CODE_START         = ORIGIN(int_flash);
    __ROM_DATA_START         = 0x10000000;
    __RAM_ITCM0_CODE_START   = __itcm0_code_start__;
    __ROM_ITCM0_CODE_START   = __itcm0_code_rom;
    __ROM_ITCM0_CODE_END     = __itcm0_code_rom_end;
    __RAM_DTCM0_DATA_START   = __dtcm0_data_start__;
    __ROM_DTCM0_DATA_START   = __dtcm0_data_rom;
    __ROM_DTCM0_DATA_END     = __dtcm0_data_rom_end;
    
    __BSS_SRAM_START         = __sram_bss_start;
    __BSS_SRAM_END           = __sram_bss_end;
    __BSS_SRAM_SIZE          = __sram_bss_end - __sram_bss_start;
    
    __BSS_SRAM_NC_START      = __non_cacheable_bss_start;
    __BSS_SRAM_NC_SIZE       = __non_cacheable_bss_end - __non_cacheable_bss_start;
    __BSS_SRAM_NC_END        = __non_cacheable_bss_end;

    __BSS_SRAM_SH_START      = __shareable_bss_start;
    __BSS_SRAM_SH_SIZE       = __shareable_bss_end - __shareable_bss_start;
    __BSS_SRAM_SH_END        = __shareable_bss_end;

    __RAM_INTERRUPT_START    = __interrupts_ram_start;
    __ROM_INTERRUPT_START    = __interrupts_rom_start;
    __ROM_INTERRUPT_END      = __interrupts_rom_end;

    __INIT_TABLE             = __init_table;
    __ZERO_TABLE             = __zero_table;
    
    __RAM_INIT               = 1;
    __ITCM_INIT              = 1;
    __DTCM_INIT              = 1;
    
    Fls_ACEraseRomStart         = __acfls_code_rom_start;
    Fls_ACEraseRomEnd           = __acfls_code_rom_end;
    Fls_ACEraseSize             = (__acfls_code_rom_end - __acfls_code_rom_start) / 4; /* Copy 4 bytes at a time*/

    Fls_ACWriteRomStart         = __acfls_code_rom_start;
    Fls_ACWriteRomEnd           = __acfls_code_rom_end;
    Fls_ACWriteSize             = (__acfls_code_rom_end - __acfls_code_rom_start) / 4; /* Copy 4 bytes at a time*/
    
    _ERASE_FUNC_ADDRESS_        = ADDR(.acfls_code_ram);
    _WRITE_FUNC_ADDRESS_        = ADDR(.acfls_code_ram);
    
    __ENTRY_VTABLE              = __ROM_INTERRUPT_START;
	
    __CORE0_VTOR             = __interrupts_rom_start;
    __CORE1_VTOR             = __interrupts_rom_start;

}

startup_cm7.s文件修改注意事项如图红框所示:

S32K312 DTCM在代码中使用示例_第2张图片

最后,通过debug单步调试,可以看到myDtcm0Data数组中已经有初始化值了,从0到10。而且myDtcm0Data的地址是0x20001000,在ld文件对应的地址范围内。

S32K312 DTCM在代码中使用示例_第3张图片

S32K312 DTCM在代码中使用示例_第4张图片

myDtcm0Data1的数据也有初始化值了,从0到10。myDtcm0Data1的地址是0x20000000,在ld文件对应的地址范围内。

S32K312 DTCM在代码中使用示例_第5张图片

到此,就可以成功使用DTCM了。

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