四位数码管显示.c

ICC mega8例子

//ICC-AVR application builder : 2009-3-10 14:16:46
// Target : M8
// Crystal: 8.0000Mhz

#include <iom8v.h>
#include <macros.h>

void port_init(void)
{
 PORTB = 0x00;
 DDRB  = 0x00;
 PORTC = 0x00; //m103 output only
 DDRC  = 0x00;
 PORTD = 0x00;
 DDRD  = 0x00;
}

//call this routine to initialize all peripherals
void init_devices(void)
{
 //stop errant interrupts until set up
 CLI(); //disable all interrupts
 port_init();

 MCUCR = 0x00;
 GICR  = 0x00;
 TIMSK = 0x00; //timer interrupt sources
 SEI(); //re-enable interrupts
 //all peripherals are now initialized
}

/************************************
用    途:微秒级延时程序
Taget   :mega8
crystal :8M
介    绍:在8M的晶振上进行us级的延时
入口参数:
*************************************/
void delay_us(int time)
{
    do
    {
        time--;
    } 
    while (time > 1);
}

/************************************
用    途:四位数码管的显示程序
Taget   :mega8
crystal :8M
介    绍:数码管共阳
	     a-PB0
		 b-PB1
		 ...
		 h-PB6
		 DP-PB7
		 -------
		 1-PC3
		 2-PC2
		 3-PC1
		 4-PC0
	     使用show_4_digit(p)
	     unsigned char数组
	  	 B用作数据口
         C用作片选
入口参数:显示数组
*************************************/
const unsigned char num[16]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,
	   			0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
void show_4_digit(unsigned char *p)
{
 unsigned char i,j;
 DDRB=0xff;
 DDRC=0xff;
 for (j=0;j<200;j++)
 {
  for (i=0;i<4;i++)
  {
    PORTC=0;//先关显示
    PORTB=~num[*(p+3-i)];//送数据
	PORTC=(0x1<<i);//开显示
	delay_us(200);//小延时
  }
 }
}

void main()
{
 unsigned char p[4]={1,2,3,4};
 port_init();
 init_devices();
 
 while(1)
 {
  show_4_digit(p);
 }
}