Question

我正在使用具有皮质m0 +核心的Atmel samd21 microcontroller。要引导加载新程序，我想擦除位于地址0x0000 0000的向量表并在那里写入新数据。我遇到了两个问题：

在地址0上执行删除操作似乎并未实际删除任何内容
当我尝试写地址0

我将尝试更改VTOR的地址，看看是否能让我随处可见（编辑它没有帮助）。除此之外，是否有人知道：

有一种方法告诉微控制器“嘿，我知道我在做什么，让我戳这个地址”
写入地址0是否存在于Cortex m0 +规范中定义的内容（我找不到任何内容），或者是实现定义的行为是不是很难？

修改

我的引导加载程序驻留在max_flash - 0x1000。我意识到这可能不是最好的事情，所以我可能会改变一些事情，以便引导加载程序（带有自己的向量表）驻留在0x0000。我仍然想知道为什么我不能写地址0x0000。皮质m0 +文档中没有任何内容表明我不应该这样做。

我检查了以下内容：

我的中断是否被禁用？（他们是，在我开始记忆之前，我有一个__asm__ volatile("cpsid if");）
更改VTOR的值会有所作为吗？（它没有）
我正在尝试删除BOOTPROT“锁定”的Flash页面吗？（不是，BOOTPROT = 7。）
是否列出了LOCK注册表中锁定的任何区域？（他们不是，LOCK = 0xffff）
是否正在尝试删除的页面执行？（不，在硬故障发生之前，后跟踪说pc = 0xf1dc。

还有其他需要检查的事项吗？

Answer 1

可悲的是Atmel（不能将这种情况归咎于微芯片这种情况在他们被同化之前）离开他们内置的SAM-BA引导程序。相反，他们提供了一个软件/源版本，你可以放置自己和一些额外的控件来分类保护该空间，但没有保护，所以它是微不足道的程序解锁和擦除或造成损害。最好不要只是制作自己的引导加载程序，更简单，更容易维护，（并尽量不要擦除）或使用SWD接口，如果不是备用产品，则需要作为竞争产品的唯一解决方案。我最终选择了后者。

我所发现的不仅仅是擦除和覆盖那个空间很容易，这很容易，一旦某些魔法被解锁，你可以有意或无意地对空间进行简单的存储以进行垃圾/覆盖。

我的代码接受或离开时，我已经读了一段时间，因为我读到了今天以外的数据表，看看你应该搜索BOOTPROT以查看这些保护位以及要更改的寄存器以禁用该保护（如果它甚至是。）

我自己或其他人可以和你一起完成数据表（但不是为了你），如果你仍然无法弄明白的话。

puts和gets只是存储和加载指令抽象。

//------------------------------------------------------------------------
//------------------------------------------------------------------------

#include "flash-bin.h"

void PUT32 ( unsigned int, unsigned int );
unsigned int GET32 ( unsigned int );
void PUT16 ( unsigned int, unsigned int );
unsigned int GET16 ( unsigned int );
void PUT8 ( unsigned int, unsigned int );
unsigned int GET8 ( unsigned int );
void dummy ( unsigned int );

#define PORT_BASE 0x41004400

#define PORTA_DIRSET (PORT_BASE+0x00+0x08)
#define PORTA_OUTCLR (PORT_BASE+0x00+0x14)
#define PORTA_OUTSET (PORT_BASE+0x00+0x18)
#define PORTA_OUTTGL (PORT_BASE+0x00+0x1C)

#define PORTB_DIRSET (PORT_BASE+0x80+0x08)
#define PORTB_OUTCLR (PORT_BASE+0x80+0x14)
#define PORTB_OUTSET (PORT_BASE+0x80+0x18)
#define PORTB_OUTTGL (PORT_BASE+0x80+0x1C)

#define PORTA_PMUX05    (PORT_BASE+0x00+0x30+5)
#define PORTA_PINCFG10  (PORT_BASE+0x00+0x40+10)
#define PORTA_PINCFG11  (PORT_BASE+0x00+0x40+11)

#define PORTB_PMUX01    (PORT_BASE+0x80+0x30+1)
#define PORTB_PMUX11    (PORT_BASE+0x80+0x30+11)
#define PORTB_PINCFG03  (PORT_BASE+0x80+0x40+3)
#define PORTB_PINCFG22  (PORT_BASE+0x80+0x40+22)
#define PORTB_PINCFG23  (PORT_BASE+0x80+0x40+23)

#define GCLK_BASE       0x40000C00
#define GCLK_CTRL       (GCLK_BASE+0x00)
#define GCLK_STATUS     (GCLK_BASE+0x01)
#define GCLK_CLKCTRL    (GCLK_BASE+0x02)
#define GCLK_GENCTRL    (GCLK_BASE+0x04)
#define GCLK_GENDIV     (GCLK_BASE+0x08)

#define PM_BASE         0x40000400
#define APBCMASK        (PM_BASE+0x20)

#define SYSCTRL_BASE    0x40000800
#define OSC8M           (SYSCTRL_BASE+0x20)

#define SERCOM5_BASE        0x42001C00
#define SERCOM5_CTRLA       (SERCOM5_BASE+0x00)
#define SERCOM5_CTRLB       (SERCOM5_BASE+0x04)
#define SERCOM5_BAUD        (SERCOM5_BASE+0x0C)
#define SERCOM5_INTFLAG     (SERCOM5_BASE+0x18)
#define SERCOM5_SYNCBUSY    (SERCOM5_BASE+0x1C)
#define SERCOM5_DATA        (SERCOM5_BASE+0x28)

#define SERCOM0_BASE        0x42000800
#define SERCOM0_CTRLA       (SERCOM0_BASE+0x00)
#define SERCOM0_CTRLB       (SERCOM0_BASE+0x04)
#define SERCOM0_BAUD        (SERCOM0_BASE+0x0C)
#define SERCOM0_INTFLAG     (SERCOM0_BASE+0x18)
#define SERCOM0_SYNCBUSY    (SERCOM0_BASE+0x1C)
#define SERCOM0_DATA        (SERCOM0_BASE+0x28)

#define STK_CSR 0xE000E010
#define STK_RVR 0xE000E014
#define STK_CVR 0xE000E018
#define STK_MASK 0x00FFFFFF

#define ACTLR 0xE000E008
#define CPUID 0xE000ED00

#define NVMCTRL_BASE 0x41004000
#define NVM_CTRLA   (NVMCTRL_BASE+0x00)
#define NVM_CTRLB   (NVMCTRL_BASE+0x04)
#define NVM_PARAM   (NVMCTRL_BASE+0x08)
#define NVM_INTFLAG (NVMCTRL_BASE+0x14)
#define NVM_STATUS  (NVMCTRL_BASE+0x18)
#define NVM_ADDR    (NVMCTRL_BASE+0x1C)
#define NVM_LOCK    (NVMCTRL_BASE+0x20)

//------------------------------------------------------------------------
static void clock_init ( void )
{
    unsigned int ra;

    ra=GET32(OSC8M);
    ra&=~(3<<8);
    PUT32(OSC8M,ra);
}
//------------------------------------------------------------------------
#ifdef USE_SERCOM0
//TX PA10  SERCOM0 PAD[2] FUNCTION C  SERCOM2 PAD[2]  FUNCTION D
//RX PA11  SERCOM0 PAD[3] FUNCTION C  SERCOM2 PAD[3]  FUNCTION D
//------------------------------------------------------------------------
static void uart_init ( void )
{
    unsigned int ra;

    ra=GET32(APBCMASK);
    ra|=1<<2; //enable SERCOM0
    PUT32(APBCMASK,ra);

    PUT32(GCLK_GENCTRL,0x00010605);

    PUT16(GCLK_CLKCTRL,0x4514);

    PUT8(PORTA_PINCFG10,0x01);
    PUT8(PORTA_PINCFG11,0x01);
    PUT8(PORTA_PMUX05,0x22);

    while(GET32(SERCOM0_SYNCBUSY)) continue;
    PUT32(SERCOM0_CTRLA,0x00000000);
    while(GET32(SERCOM0_SYNCBUSY)) continue;
    PUT32(SERCOM0_CTRLA,0x00000001);
    while(GET32(SERCOM0_SYNCBUSY)) continue;
    PUT32(SERCOM0_CTRLA,0x40310004);
    while(GET32(SERCOM0_SYNCBUSY)) continue;
    PUT32(SERCOM0_CTRLB,0x00030000);
    while(GET32(SERCOM0_SYNCBUSY)) continue;
    PUT16(SERCOM0_BAUD,50436);
    while(GET32(SERCOM0_SYNCBUSY)) continue;
    PUT32(SERCOM0_CTRLA,0x40310006);
    while(GET32(SERCOM0_SYNCBUSY)) continue;
}
//------------------------------------------------------------------------
//static void uart_flush ( void )
//{
    //while(1)
    //{
        //if(GET8(SERCOM0_INTFLAG)&2) break;
    //}
//}
//------------------------------------------------------------------------
static void uart_send ( unsigned int d )
{
    while(1)
    {
        if(GET8(SERCOM0_INTFLAG)&1) break;
    }
    PUT8(SERCOM0_DATA,d&0xFF);
}
//------------------------------------------------------------------------
//static unsigned int uart_recv ( void )
//{
    //while(1)
    //{
        //if(GET8(SERCOM0_INTFLAG)&4) break;
    //}
    //return(GET8(SERCOM0_DATA)&0xFF);
//}
//------------------------------------------------------------------------
#else
//TX PB22   SERCOM5 PAD[2] PORT FUNCTION D
//RX PB23   SERCOM5 PAD[3] PORT FUNCTION D
//------------------------------------------------------------------------
static void uart_init ( void )
{
    unsigned int ra;

    ra=GET32(APBCMASK);
    ra|=1<<7; //enable SERCOM5
    ra|=1<<2; //enable SERCOM0
    PUT32(APBCMASK,ra);

    PUT32(GCLK_GENCTRL,0x00010605);

    PUT16(GCLK_CLKCTRL,0x4519);

    PUT8(PORTB_PINCFG22,0x01);
    PUT8(PORTB_PINCFG23,0x01);
    PUT8(PORTB_PMUX11,0x33);

    while(GET32(SERCOM5_SYNCBUSY)) continue;
    PUT32(SERCOM5_CTRLA,0x00000000);
    while(GET32(SERCOM5_SYNCBUSY)) continue;
    PUT32(SERCOM5_CTRLA,0x00000001);
    while(GET32(SERCOM5_SYNCBUSY)) continue;
    PUT32(SERCOM5_CTRLA,0x40310004);
    while(GET32(SERCOM5_SYNCBUSY)) continue;
    PUT32(SERCOM5_CTRLB,0x00030000);
    while(GET32(SERCOM5_SYNCBUSY)) continue;
    PUT16(SERCOM5_BAUD,50436);
    while(GET32(SERCOM5_SYNCBUSY)) continue;
    PUT32(SERCOM5_CTRLA,0x40310006);
    while(GET32(SERCOM5_SYNCBUSY)) continue;
}
//------------------------------------------------------------------------
//static void uart_flush ( void )
//{
    //while(1)
    //{
        //if(GET8(SERCOM5_INTFLAG)&2) break;
    //}
//}
//------------------------------------------------------------------------
static void uart_send ( unsigned int d )
{
    while(1)
    {
        if(GET8(SERCOM5_INTFLAG)&1) break;
    }
    PUT8(SERCOM5_DATA,d&0xFF);
}
//------------------------------------------------------------------------
//static unsigned int uart_recv ( void )
//{
    //while(1)
    //{
        //if(GET8(SERCOM5_INTFLAG)&4) break;
    //}
    //return(GET8(SERCOM5_DATA)&0xFF);
//}
//------------------------------------------------------------------------
#endif
//------------------------------------------------------------------------
static void hexstrings ( unsigned int d )
{
    //unsigned int ra;
    unsigned int rb;
    unsigned int rc;

    rb=32;
    while(1)
    {
        rb-=4;
        rc=(d>>rb)&0xF;
        if(rc>9) rc+=0x37; else rc+=0x30;
        uart_send(rc);
        if(rb==0) break;
    }
    uart_send(0x20);
}
//------------------------------------------------------------------------
static void hexstring ( unsigned int d )
{
    hexstrings(d);
    uart_send(0x0D);
    uart_send(0x0A);
}
//------------------------------------------------------------------------
static void flash_busy ( void )
{
    while(1)
    {
        if(GET8(NVM_INTFLAG)&(1<<0)) break;
    }
}
//------------------------------------------------------------------------
static void flash_command ( unsigned int cmd )
{
    PUT16(NVM_CTRLA,0xA500+cmd);
    flash_busy();
}
//------------------------------------------------------------------------
#define FLASH_ER 0x02
#define FLASH_WP 0x04
#define FLASH_UR 0x41
#define FLASH_PBC 0x44
#define FLASH_INVALL 0x46
//------------------------------------------------------------------------
int notmain ( void )
{
    unsigned int ra;
    unsigned int addr;
    unsigned int page_size;
    unsigned int row_size;
    unsigned int pages;
    unsigned int rows;


    clock_init();
    uart_init();
    hexstring(0x12345678);
    hexstring(GET32(ACTLR));
    hexstring(GET32(CPUID));
    hexstring(GET32(NVM_PARAM));
    ra=GET32(NVM_PARAM);
    pages=ra&0xFFFF;
    page_size=(ra>>16)&7;
    page_size=8<<page_size;
    row_size=page_size<<2;
    rows=pages>>2;
    hexstring(pages);
    hexstring(page_size);
    hexstring(rows);
    hexstring(row_size);

    flash_busy();
    flash_command(FLASH_INVALL); //where do you use this if at all?
    for(addr=0x0000;addr<0x8000;addr+=0x100)
    {
        hexstrings(addr); hexstring(GET8(NVM_INTFLAG));
        PUT32(NVM_ADDR,addr);
        flash_command(FLASH_UR); //unlock
        flash_command(FLASH_ER); //erase row
    }

    for(ra=0x0000;ra<0x0040;ra+=4)
    {
        hexstrings(ra); hexstring(GET32(ra));
    }

if(1)
{
    flash_command(FLASH_INVALL); //where do you use this if at all?
    flash_command(FLASH_PBC); //page buffer clear
    for(addr=0x0000,ra=0;ra<(0x800>>2);ra++,addr+=4)
    {
        if((addr&0x3F)==0) hexstring(addr);
        PUT32(addr,rom[ra]);
        if((addr&0x3F)==0x3C) flash_busy();
    }
    for(ra=0x0000;ra<0x0040;ra+=4)
    {
        hexstrings(ra); hexstring(GET32(ra));
    }
}

    return(0);
}
//------------------------------------------------------------------------
//------------------------------------------------------------------------

由于几乎所有有用的SWD / JTAG调试器都允许您在ram中下载和运行程序，但并非所有调试器都支持所有编程闪存的细微差别，我个人的偏好是要么有一个程序ram带有一个有效载荷，它是一个flash程序，它在应用程序中对它进行编程，这样就可以使用任何调试器。那个或者我写一个bootloader，如果没有足够的ram或者使用ram程序来烧掉bootloader然后引导程序来烧掉更大的应用程序...... YMMV做你自己的事情。

修改

sram.s

.cpu cortex-m0
.thumb

.thumb_func
.global _start
_start:
    ldr r0,stacktop
    mov sp,r0
    bl notmain
    b hang
.thumb_func
hang:   b .

.align
stacktop: .word 0x20001000

.thumb_func
.globl PUT8
PUT8:
    strb r1,[r0]
    bx lr

.thumb_func
.globl PUT16
PUT16:
    strh r1,[r0]
    bx lr

.thumb_func
.globl PUT32
PUT32:
    str r1,[r0]
    bx lr

.thumb_func
.globl GET8
GET8:
    ldrb r0,[r0]
    bx lr

.thumb_func
.globl GET16
GET16:
    ldrh r0,[r0]
    bx lr

.thumb_func
.globl GET32
GET32:
    ldr r0,[r0]
    bx lr

.thumb_func
.globl dummy
dummy:
    bx lr

.end

sram.ld

MEMORY
{
    ram : ORIGIN = 0x20000000, LENGTH = 0xD00
}

SECTIONS
{
    .text : { *(.text*) } > ram
    .rodata : { *(.rodata*) } > ram
    .bss : { *(.bss*) } > ram
}

无法擦除samd21单片机闪存的第一页

1 个答案: