/****************************************
用定時器維持數(shù)碼管顯示
現(xiàn)在是數(shù)碼管示數(shù)不斷增加。
****************************************/
#include <iom16v.h>

unsigned int cnt;
unsigned char shu[8];
unsigned char aa;
const unsigned char duanma[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,
                              0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
const unsigned char weima[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};

/***************************************
             數(shù)據(jù)轉(zhuǎn)換子函數(shù)
***************************************/
void change(unsigned int i)
{
 shu[0]=duanma[i/1000];
 shu[1]=duanma[i/100%10];
 shu[2]=duanma[i%100/10];
 shu[3]=duanma[i%10];
}

/****************************************
               延時函數(shù)
****************************************/
void delay(unsigned int t)
{
   unsigned int x,y;
   for(x=t;x>0;x--)
    for(y=100;y>0;y--);
}

/****************************************
               顯示函數(shù)
****************************************/
void display(unsigned char i)
{
  PORTB =0X00;
  PORTA|=0X01;
  PORTA&=0XFE;
  
  PORTB =weima[i];
  PORTA|=0x02;
  PORTA&=0XFD;
  
  PORTB=shu[i];
  PORTA|=0X01;
  PORTA&=0XFE;
}

/***************************************
             端口初始化
***************************************/
void init_port(void)
{
 PORTA=0XFF;
 DDRA=0XFF;
 PORTB=0XFF;
 DDRB=0XFF;
}

/***************************************
             定時器0初始化
***************************************/
void timer0_init(void)
{
 TCNT0=0X83; //1MS的定時初值
 TCCR0=0X03; //定時器的計數(shù)預分頻取64
}

/***************************************
             定時器0服務(wù)函數(shù)
***************************************/
#pragma interrupt_handler timer0_ovf_isr:10
void timer0_ovf_isr(void)
{
 TCNT0=0X83; //重裝1ms的定時初值
 if(++aa>3) aa=0;
  switch(aa)
  {
    case 0: display(0);break;
 case 1: display(1);break;
 case 2: display(2);break;
 case 3: display(3);break;
 default:break;
  }
}

void main(void)
{
 init_port();   //IO端口初始化
 timer0_init(); //定時器1初始化 
 TIMSK=0X01;    //使能T0中斷 
 SREG=0X80;     //使能總中斷
 while(1)
 {
  cnt++;
  delay(1000);
  change(cnt);
 }
}

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