中断-timer0

使用timer0中断，将LED灯闪烁

Init.c

/* * init.c: 进行一些初始化 */ #include "s3c24xx.h" void disable_watch_dog(void);void clock_init(void);void memsetup(void);void copy_steppingstone_to_sdram(void);void init_led(void);void timer0_init(void);void init_irq(void);void delay(int n){int i; for(i=0;i<n;i++);}/* * 关闭WATCHDOG，否则CPU会不断重启 */void disable_watch_dog(void){    // 关闭WATCHDOG很简单，往WTCON寄存器写0即可    WTCON = 0;}#define S3C2410_MPLL_200MHZ     ((0x5c<<12)|(0x04<<4)|(0x00))#define S3C2440_MPLL_200MHZ     ((0x5c<<12)|(0x01<<4)|(0x02))/* * 对于MPLLCON寄存器，[19:12]为MDIV，[9:4]为PDIV，[1:0]为SDIV * 有如下计算公式： *  S3C2410: MPLL(FCLK) = (m * Fin)/(p * 2^s) *  S3C2410: MPLL(FCLK) = (2 * m * Fin)/(p * 2^s) *  其中: m = MDIV + 8, p = PDIV + 2, s = SDIV * 对于本开发板，Fin = 12MHz * 设置CLKDIVN，令分频比为：FCLK:HCLK:PCLK=1:2:4， * FCLK=200MHz,HCLK=100MHz,PCLK=50MHz */void clock_init(void){    // LOCKTIME = 0x00ffffff;   // 使用默认值即可    CLKDIVN  = 0x03;            // FCLK:HCLK:PCLK=1:2:4, HDIVN=1,PDIVN=1    /* 如果HDIVN非0，CPU的总线模式应该从“fast bus mode”变为“asynchronous bus mode” */__asm__(    "mrc    p15, 0, r1, c1, c0, 0\n"        /* 读出控制寄存器 */     "orr    r1, r1, #0xc0000000\n"          /* 设置为“asynchronous bus mode” */    "mcr    p15, 0, r1, c1, c0, 0\n"        /* 写入控制寄存器 */    );    /* 判断是S3C2410还是S3C2440 */    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))    {        MPLLCON = S3C2410_MPLL_200MHZ;  /* 现在，FCLK=200MHz,HCLK=100MHz,PCLK=50MHz */    }    else    {        MPLLCON = S3C2440_MPLL_200MHZ;  /* 现在，FCLK=200MHz,HCLK=100MHz,PCLK=50MHz */    }       }/* * 设置存储控制器以使用SDRAM */void memsetup(void){    volatile unsigned long *p = (volatile unsigned long *)MEM_CTL_BASE;    /* 这个函数之所以这样赋值，而不是像前面的实验(比如mmu实验)那样将配置值     * 写在数组中，是因为要生成”位置无关的代码”，使得这个函数可以在被复制到     * SDRAM之前就可以在steppingstone中运行     ,steppingstone是在S3C2440 中，实际上是一块4k大小的SRAM     */    /* 存储控制器13个寄存器的值 */    p[0] = 0x22011110;     //BWSCON    p[1] = 0x00000700;     //BANKCON0    p[2] = 0x00000700;     //BANKCON1    p[3] = 0x00000700;     //BANKCON2    p[4] = 0x00000700;     //BANKCON3      p[5] = 0x00000700;     //BANKCON4    p[6] = 0x00000700;     //BANKCON5    p[7] = 0x00018005;     //BANKCON6    p[8] = 0x00018005;     //BANKCON7        /* REFRESH,     * HCLK=12MHz:  0x008C07A3,     * HCLK=100MHz: 0x008C04F4     */     p[9]  = 0x008C04F4;    p[10] = 0x000000B1;     //BANKSIZE    p[11] = 0x00000030;     //MRSRB6    p[12] = 0x00000030;     //MRSRB7}void copy_steppingstone_to_sdram(void){    unsigned int *pdwSrc  = (unsigned int *)0;    unsigned int *pdwDest = (unsigned int *)0x30000000;        while (pdwSrc < (unsigned int *)4096)    {        *pdwDest = *pdwSrc;        pdwDest++;        pdwSrc++;    }}#define GPFCON              (*(volatile unsigned long *)0x56000050)#defineGPF4_out(1<<(4*2))#defineGPF5_out(1<<(5*2))#defineGPF6_out(1<<(6*2))/* * K1-K4对应GPG11、GPG3、GPF2、GPF3 */#define GPG11_eint      (2<<(11*2))     // K1,EINT19#define GPG3_eint       (2<<(3*2))      // K2,EINT11#define GPF3_eint       (2<<(3*2))      // K3,EINT3#define GPF2_eint       (2<<(2*2))      // K4,EINT2 void init_led(void){GPFCON = GPF4_out|GPF5_out|GPF6_out;// 将LED1,2,4对应的GPF4/5/6三个引脚设为输出}/* * Timer input clock Frequency = PCLK / {prescaler value+1} / {divider value} * {prescaler value} = 0~255 * {divider value} = 2, 4, 8, 16 * 本实验的Timer0的时钟频率=100MHz/(99+1)/(16)=62500Hz * 设置Timer0 0.5秒钟触发一次中断： */void timer0_init(void){// 预分频器0 = 99    TCFG0 &= ~0xFF;TCFG0 |= 0x63;// 选择16分频TCFG1 &= ~0x0F;TCFG1 |= 0x03;// 0.5秒钟触发一次中断TCNTB0 = 15625;//设定的计数 次数   递减TCMPB0 = 0;//比较，减到这个数// 手动更新TCON &= ~(1<<1);TCON |= 1<<1;// 自动加载，清“手动更新”位，启动定时器0//TCON &= ~0X03;//TCON |= 0x01;//TCON |= (3<<0);TCON &= ~(1<<1);//清“手动更新”位TCON |=(1<<3);//自动加载TCON |=(1<<0);//启动定时器0}/* * 定时器0中断使能 */ void init_irq(void){            // 定时器0中断使能,INTMSKINTMSK &= ~ (1<<10);//中断屏蔽寄存器}

Interrupt.c

#include "s3c24xx.h"int flag=0;void Timer0_Handle(void){    /*     * 每次中断令4个LED改变状态     */     unsigned long oft = INTOFFSET;//读取中断偏移量//成功的if(oft==10)//根据偏移量，判断是不是timer0中断{if(flag==0){GPFDAT &= ~(1<<4|1<<5|1<<6);//亮灯flag=1;}else{GPFDAT |= (1<<4|1<<5|1<<6);//关灯flag=0;}SRCPND=SRCPND;INTPND=INTPND;//SRCPND &= ~(1<<10);//INTPND &= ~(1<<10);//SRCPND = 0;//INTPND = 0;}}