这一节我们将讲解数码管的使用，由于原理在学51单片机的时候已经学习过，在这里只需要利用前面学习的对AVR单片机的IO口操作方式就可以自己写练习题了。

下面的数码管是共阳极数码管。

代码：显示从0到9。

/*
*author:ChenLu
*date:2014.11.20
*/

//input the head file so that the program can work normally
//iom16v---know the register
//macros---know the BIT(x)
#include<iom16v.h>
#include<macros.h>
//use those can make your study very conveninet
#define uint unsigned int
#define uchar unsigned char

//display methods 
void initSystem();
void delay();

//display the variable data
uchar flag;
uchar table[10] = {0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};

//the main function
void main()
{
 	//init your system
	initSystem();
	while(1)
	{
	  	//start your function,and this is core solution
		for(flag=0;flag<10;flag++)
		{
            <span style="white-space:pre">		</span>PORTB = table[flag];
			delay();
			delay();
			delay();
			delay();
			delay();
			delay();
			delay();
		}	 	 
	}
}

//the method of init system
void initSystem()
{
 	//to make PB port output 
	DDRB = 0xFF;
	//to make PB port output high level
	PORTB = 0xFF;
}

//the sub method of delay
void delay()
{
 	uchar i,j;
 	for(i=0;i<200;i++)
	  for(j=0;j<200;j++);
}

AVR第6课：数码管显示