我的AVR资料[程序篇] 数码管显示(源码9)

正点原子

这个驱动8位数码管的代码,用avr的是会,这个数码管用得最多了.使用了74ls138和cd4511译码器,驱动代码如下:
#include<mega16.h>
#include<stdlib.h>
#include<delay.h>
#define uchar unsigned char
#define uint unsigned int

void delay(unsigned char time)//delay function
{
    unsigned char b;
  for(;time>0;time--)
 for(b=50;b>0;b--);
}
//digital number display function, the first parameter is the number you want to show
//the second parameter is the position of the number
void display(unsigned char number,unsigned char position);
void systeminit()//a simple system initialization function
{
 DDRA=0Xff;//set PORTA output
 ORTA=0XFF;//set PORTA output in high level
}
void main(void)
{
    unsigned char b1,b2,b3,b4,b5,b6,b7,b8;
 uchar key,temp=1;
 unsigned long t=0;
 systeminit();
 while(1)
 {
   b1=t%10;display(b1,8);//delay(5);
   b2=(t/10)%10;display(b2,7);//delay(5);
   b3=(t/100)%10;display(b3,6);//delay(5);
   b4=(t/1000)%10;display(b4,5);//delay(5);
   b5=(t/10000)%10;display(b5,4);//delay(5);
   b6=(t/100000)%10;display(b6,3);//delay(5);
   b7=(t/1000000)%10;display(b7,2);//delay(5);
    b8=(t/10000000)%10;display(b8,1);//delay(4);
   if(t>99999999)t=0;delay_us(100);//?'??
   t++;
    }
}
void display(unsigned char number,unsigned char position)//digtial show function
{  
    DDRA=0Xff;//set PORTA output
 ORTA=0XFF;//set PORTA output in high level
    switch(position)//choice the position
 {
  case 1:{PORTA&=0xf8;break;}
  case 2:{PORTA&=0xf9;break;}
  case 3:{PORTA&=0Xfa;break;}
  case 4:{PORTA&=0Xfb;break;}
  case 5:{PORTA&=0Xfc;break;}
  case 6:{PORTA&=0Xfd;break;}
  case 7:{PORTA&=0Xfe;break;}
  case 8:{PORTA&=0Xff;break;}
  } 
    switch(number)//show number
 {
  case 0:{PORTA&=0x87;break;}    //0
  case 1:{PORTA&=0x8f;break;}    //1
  case 2:{PORTA&=0x97;break;}    //2
  case 3:{PORTA&=0x9f;break;}    //3
  case 4:{PORTA&=0xa7;break;}    //4
     case 5:{PORTA&=0xaf;break;}    //5
  case 6:{PORTA&=0xb7;break;}    //6
  case 7:{PORTA&=0xbf;break;}    //7
  case 8:{PORTA&=0xc7;break;}    //8
     case 9:{PORTA&=0xcf;break;}    //9
  default:{PORTA=0xff;break;}    //null
 }       
}