demo_6_5.c

AVR单片机嵌入式系统原理与应用实践例码

/*********************************************
File name			: demo_6_5.c
Chip type           : ATmega16
Program type        : Application
Clock frequency     : 4.000000 MHz
Memory model        : Small
External SRAM size  : 0
Data Stack size     : 256
*********************************************/

#include <mega16.h>
#include <delay.h>

flash unsigned char led_7[10]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};
flash unsigned char position[6]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf};
unsigned char time[3];					// 时、分、秒计数
unsigned char dis_buff[6];				// 显示缓冲区，存放要显示的6个字符的段码值
unsigned char time_counter;				// 1秒计数器
bit point_on;					// 秒显示标志

void display(void)				// 扫描显示函数，执行时间12ms
{
	unsigned char i;
 	for(i=0;i<=5;i++)
	{
		PORTA = led_7[dis_buff[i]]; 
		if (point_on && ( i==2 || i==4 )) PORTA |= 0x80;	// (1)
		PORTC = position[i]; 
       	delay_ms(2);									// (2)
       	PORTC = 0xff;									// (3)
  	}
}

void time_to_disbuffer(void)			// 时间值送显示缓冲区函数
{
	unsigned char i,j=0;
	for (i=0;i<=2;i++)
	{
		dis_buff[j++] = time[i] % 10;
		dis_buff[j++] = time[i] / 10;
	}
}

void main(void)
{
    PORTA=0x00;		// PORTA初始化
    DDRA=0xFF;
    PORTC=0x3F;		// PORTC初始化
    DDRC=0x3F;

    time[2] = 23; time[1] = 58; time[0] = 55;	// 时间初值23:58:55
    time_to_disbuffer();

    while (1)
    {
	    display();						// 显示扫描，执行时间12ms
	    if (++time_counter >= 40)
	    {
		    time_counter = 0;				// （4）
		    point_on = ~point_on;			// （5）
		    if (++time[0] >= 60)
		    {
			    time[0] = 0;
			    if (++time[1] >= 60)
			    {
				    time[1] = 0;
				    if (++time[2] >= 24) time[2] = 0;
			    }
		    }
		    time_to_disbuffer();
	    }
        delay_ms(13);					// 延时13ms，可进行其它处理（6）
    }
}