/*********************************************
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>  
#define uchar unsigned char 
#define uint unsigned int 

/**********************數碼管顯示相關宏定義*******************************/  
flash uchar led_7[10]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};   //共陽極數碼管
flash uchar position[4]={0x80,0x40,0x20,0x10};    //位選               

uchar time[3];				        // 時、分、秒計數
uchar dis_buff[4];              // 顯示緩沖區，存放要顯示的4個字符的段碼值                                    				
uchar time_counter;				// 1秒計數器
bit point_on;			                // 秒顯示標志

// 時間顯示函數，執行時間12ms
void time_display(void)				
{
	uchar i;
 	for(i=0;i<=3;i++)
	{       
	        PORTD &= 0x0F;
		PORTC = led_7[dis_buff[i]]; 
		if (point_on && ( i==2)) PORTC &= 0x7F;	
		PORTD|= position[i]; 
       	        delay_ms(3);
       	        PORTD&=0X0F;																	
  	}
}

// 時間值送顯示緩沖區函數
void time_to_disbuffer(void)			
{
	uchar i,j=0;
	for (i=1;i<=2;i++)
	{
		dis_buff[j++] = time[i] % 10;
		dis_buff[j++] = time[i] / 10;
	}
}

/**********************MCU初始化*******************************/
void mcu_init(void)
{
        DDRA=0X1D;  //00011101 
        DDRB=0XB1;  //10110001
        PORTB=0X00;
        DDRC=0XFF;
        PORTC=0XFF;
        DDRD=0XF0;
        PORTD=0X00;
} 

/**********************主函數*******************************/  
void main()
{
        mcu_init();
        time[2] = 23; time[1] = 58; time[0] = 55;	// 時間初值23:58:55
        time_to_disbuffer();
        
         while (1)
       {
	    time_display();						// 顯示掃描，執行時間12ms
	    if (++time_counter >= 40)
	    {
		    time_counter = 0;				
		    point_on = ~point_on;			
		    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);
      } 
}