s5pv210——中断

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1:s5pv210的中断步骤

(1):建立异常向量表;

(2):中断初始化;

(3):使能(如外部中断,写中断处理函数);

(4):建立中断号与中断处理函数的联系,使能中断;

当中断发生时,中断处理函数会自动处理中断;

流程如下:

 

2:建立异常向量表:

s5pv210异常向量表的基地址为0xD003_7400,下图为异常对于基地址的偏移量;

 

 第一步建立异常向量表:

代码如下:

/*
* s5pv210 裸机
*
* 异常向量表初始化
*
*/

#define VECTOR_TABLE_BASE 0xD0037400

#define Reset_offset 0x0
#define Undef_offset 0x4
#define SVC_offset 0x8
#define Prectch_offset 0xC
#define Data_Abort_offset 0x10
#define IRQ_offset 0x18
#define FIQ_offset 0x1C


#define _PFUNC_Reset (*(unsigned int*)(VECTOR_TABLE_BASE+Reset_offset))
#define _PFUNC_Undef (*(unsigned int*)(VECTOR_TABLE_BASE+Undef_offset))
#define _PFUNC_SVC (*(unsigned int*)(VECTOR_TABLE_BASE+SVC_offset))
#define _PFUNC_Prectch (*(unsigned int*)(VECTOR_TABLE_BASE+Prectch_offset))
#define _PFUNC_Data_Abort (*(unsigned int*)(VECTOR_TABLE_BASE+Data_Abort_offset))
#define _PFUNC_IRQ (*(unsigned int*)(VECTOR_TABLE_BASE+IRQ_offset))
#define _PFUNC_FIQ (*(unsigned int*)(VECTOR_TABLE_BASE+FIQ_offset))

extern void IRQ_handle(void);


void Reset_handle(void)
{

}
void Undef_handle(void)
{

}

void SVC_handle(void)
{

}
void Prectch_handle(void)
{

}
void Data_Abort_handle(void)
{

}

 

 


void vector_table_init(void)
{
_PFUNC_Reset =   (unsigned int)Reset_handle;
_PFUNC_Undef =   (unsigned int)Undef_handle;
_PFUNC_SVC =    (unsigned int)SVC_handle;
_PFUNC_Prectch = (unsigned int)Prectch_handle;
_PFUNC_Data_Abort = (unsigned int)Data_Abort_handle;
_PFUNC_IRQ =     (unsigned int)IRQ_handle;
_PFUNC_FIQ =     (unsigned int)IRQ_handle; //FIQ、IRQ都是采用IRQ中断

}

 

 

IRQ_handle要写在汇编IRQ_handle.S中;

代码如下:

/*
 *
 *
 *
 *
 */

#define IRQ_STACK        0xD0037F80 
    
    .global IRQ_handle
IRQ_handle:

    //设置IRQ的栈
    ldr sp, =IRQ_STACK

    //由于三级流水线的存在,pc为此时的程序语句+8,保存的时候要把下一句保存到lr中
    sub lr, lr, #4
    
    //保存现场
    stmd sp! {r0-r12, lr}
    
    //跳转到中断处理函数
    bl isr_handler
    
    //恢复现场
    ldmfd sp! {r0-r8, pc}^

ARM保存中断时为什么使用 sub lr, lr, #4

1. 首先要谈流水线,在arm执行过程中一般分为取指,译码,执行阶段

  也就是假设当前                                                                      第一条指令在执行阶段

                                                              第二条指令在译码阶段

                          第三条指令在取指阶段

  当前正在执行的指令地址为pc-8,第二条就为pc-4,而pc现在真正指向已处于pc位置

 

2. 一般pc在发生中断时lr保存的是当前的pc值,这里pc值是多少呢??

     当发生中断肯定保存的pc是第三条指令,而我们从中断返回肯定不是执行第三条指令,而是紧接着的第二条指令,所以应该保存的 lr = pc - 4,

但是当执行到此位置时pc值已经改变,肯定不对,还好发生中断时 mov lr,pc 所以这里就可以直接使用 sub lr,lr,#4

 

————————————————————未完待续————————————————————————————

第二部:中断初始化

相关寄存器:

使能中断:

Disable中断

中断处理函数自动保存地址

 中断处理函数存放地址

代码实战:

//清除4个中断处理函数
void clean_vicaddress(void)
{
    _REG_VIC0ADDRESS = 0x0;
    _REG_VIC1ADDRESS = 0x0;
    _REG_VIC2ADDRESS = 0x0;
    _REG_VIC3ADDRESS = 0x0;
    
}


 
void interrupt_init(void)
{
    //第一步初始化中断之前要关闭所有中断
    _REG_VIC0INTENCLEAR = 0xFFFFFFFF;
    _REG_VIC1INTENCLEAR = 0xFFFFFFFF;
    _REG_VIC2INTENCLEAR = 0xFFFFFFFF;
    _REG_VIC3INTENCLEAR = 0xFFFFFFFF;
    
    //第三步:设置中断为IRQ中断
    _REG_VIC0INTSELECT = 0x0;
    _REG_VIC1INTSELECT = 0x0;
    _REG_VIC2INTSELECT = 0x0;
    _REG_VIC3INTSELECT = 0x0;
    
    //第三步:清中断处理函数地址
    clean_vicaddress();
    
}

void int_disable(unsigned int num)
{
    if (num < 32) {
        _REG_VIC0INTENCLEAR = (0x1<<num);
    }
    else if (num < 64) {
        _REG_VIC1INTENCLEAR = (0x1<<(num-32));        
    }
    else if (num < 96) {
        _REG_VIC2INTENCLEAR = (0x1<<(num-64));
    }
    else if (num < 128) {
        _REG_VIC3INTENCLEAR = (0x1<<(num-96));
    }
    else {

    }
        
}
 
void int_enable(unsigned int num)
{
    if (num < 32) {
        _REG_VIC0INTENABLE = (0x1<<num);
    }
    else if (num < 64) {
        _REG_VIC1INTENABLE = (0x1<<(num-32));        
    }
    else if (num < 96) {
        _REG_VIC2INTENABLE = (0x1<<(num-64));
    }
    else if (num < 128) {
        _REG_VIC3INTENABLE = (0x1<<(num-96));
    }
    else {
        _REG_VIC0INTENABLE = 0xFFFFFFFF;
        _REG_VIC1INTENABLE = 0xFFFFFFFF;
        _REG_VIC2INTENABLE = 0xFFFFFFFF;
        _REG_VIC3INTENABLE = 0xFFFFFFFF;
    }
    
}
 
void creat_israddr(unsigned int num, void (*PIRQ_handler)(void))
{
    
    if (num < 32) {        
        //*( (void (*)(void))(VIC0VECTADDR + 4*num) )= PIRQ_handler;
        *( (volatile unsigned long *)(VIC0VECTADDR + 4*(num-0)) ) = (unsigned)PIRQ_handler;
        
    }
    else if (num < 64) {
        //(void (*)(void))(VIC1VECTADDR + 4*(num-32))= PIRQ_handler;
        *( (volatile unsigned long *)(VIC1VECTADDR + 4*(num-32)) ) = (unsigned)PIRQ_handler;
    }
    else if (num < 96) {
        //(void (*)(void))(VIC2VECTADDR + 4*(num-64))= PIRQ_handler;
        *( (volatile unsigned long *)(VIC2VECTADDR + 4*(num-64)) ) = (unsigned)PIRQ_handler;
    }
    else {
        //(void (*)(void))(VIC3VECTADDR + 4*(num-96))= PIRQ_handler;
        *( (volatile unsigned long *)(VIC3VECTADDR + 4*(num-96)) ) = (unsigned)PIRQ_handler;
    }
        
}
 
//判断中断在哪个address中

static int check_int_addr(void)
{
    if (_REG_VIC0IRQSTATUS) {
        return 0;
    }
    else if (_REG_VIC1IRQSTATUS) {
        return 1;
    }
    else if (_REG_VIC2IRQSTATUS) {
        return 2;
    }
    else if (_REG_VIC3IRQSTATUS) {
        return 3;
    }
    else {
        return -1;
    }
    
} 
 

void isr_handler(void)
{
    void (*p_isr)(void) = NULL;
    int i;
    
    i = check_int_addr();
    switch (i) {
        case 0 :
            p_isr = (void (*)(void))_REG_VIC0ADDRESS;
            break;
        case 1 :
            p_isr = (void (*)(void))_REG_VIC1ADDRESS;
            break;
        case 2 :
            p_isr = (void (*)(void))_REG_VIC2ADDRESS;
            break;
        case 3 :
            p_isr = (void (*)(void))_REG_VIC2ADDRESS;
            break;
        default :
            break;
    }
    
    p_isr();
    
}

 

第三部:使能外部中断中断处理函数;

详细请看

void int_led_blink(void)
{
   //中断处理函数 
  led_blink();
  //清楚外部中断挂起,注意写1清挂起 clean_int_pend(); //清
vicaddress

  clean_vicaddress();
}

 

第四部:建立中断号与中断函数联系,使能中断

#include "interrupt.h"
#include "stdio.h"
extern void led_blink(void);
extern void led1_on(void);
extern void vector_table_init(void);
extern void key_init(void);
extern void uart_init(void);

int main(void)
{
    //按键初始化
    key_inter_init();
    
    //异常向量表初始化
    vector_table_init();
    
    //中断初始化
    interrupt_init();
    
    
    //创建函数
    creat_israddr(NUM_EINT2, int_led_blink);
    creat_israddr(NUM_EINT3, int_led_blink);
    creat_israddr(NUM_EINT16_31, int_led_blink);
    
    
    //使能中断
    int_enable(NUM_EINT2);
    int_enable(NUM_EINT3);
    int_enable(NUM_EINT16_31);
    
    
    while (1) {
        printf("a");
    }
    
}

 

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