#include <reg51.h>
#include <intrins.h>

#define RL(x) _crol_(x,1);    // 重新定義 RL左旋函式

unsigned char code font[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71}; //0~9,a~f之7段顯示器顯示字型內容

void delay(unsigned int t);
unsigned char key(unsigned char y);

unsigned char i,scan,kb_buf,x,tmp;
unsigned char led_buffer[8];

void main(void)
{
   for(i=0;i<8;i++)           
     led_buffer[i] = 0;  //將第0至7位數內容預設值皆為0, 7段顯示器全暗
   TMOD = 0x01;        //設定Timer0工作於模式1
   TH0 = (65536-2000) / 256;    //給予初值, 2ms中斷一次
   TL0 = (65536-2000) % 256;
   TR0 = 1;     //啟動計時器
   IE = 0x82;   //啟動Timer0中斷
   scan = 0; 
   while(1)
   {  
     kb_buf = 0xfe;
     for (x=0;x<4;x++)
      { P0 = kb_buf;
 	    tmp = P0;
        while((tmp & 0xf0) != 0xf0)       //將P0.3~P0.0清為0, 判斷P0.7~P0.4是否皆為1,如果不是,代表有按鍵被壓下
	     {
         delay(3);          //延遲, 判斷是否為彈跳訊號
		 tmp = P0;
	     if ((tmp & 0xf0) != 0xf0)        //如果P0.7~P0.4仍然有0的情況, 則表示非彈跳訊號
		    {
	          led_buffer[0] = led_buffer[1];       //7段顯示器資料向左移動
 	          led_buffer[1] = led_buffer[2];
	          led_buffer[2] = led_buffer[3];
	          led_buffer[3] = led_buffer[4];
	          led_buffer[4] = led_buffer[5];
	          led_buffer[5] = led_buffer[6];
	          led_buffer[6] = led_buffer[7];
			  led_buffer[7] = font[key(tmp)];      //將按鍵值送到最右邊7段顯示器顯示
			}
		 
        do {
		     tmp = P0;                       //讀回按鍵值
		   }while((tmp & 0xf0) != 0xf0);     //直到P0.7~P0.4皆為1為止(代表按鍵已放開)
         }
		kb_buf = RL(kb_buf);
      }
   }
}


void scan_7seg()  interrupt 1    //Timer0中斷程式(中斷向量1)
{
							
   TH0 = (65536-2000) / 256;  //重設一次初值
   TL0 = (65536-2000) % 256;
   P1 = 0xf8 + scan;          //控制第n位數導通,並將P1.7~P1.4設為1
   P2 = led_buffer[scan++];	  //送出第n位數要顯示之字型資料, 並將位置加1,只到下一個位數				
   if(scan==8)				  //判斷是否到第8位數,如果是則歸0
      scan=0;					
}

unsigned char key(unsigned char y)   //將按鍵轉成對應鍵值副程式
{
   unsigned char key_data;
   switch(y)
     {
	   case 0xee:
	        key_data = 0;
			break;
	   case 0xed:
	        key_data = 1;
			break;
	   case 0xeb:
	        key_data = 2;
			break;
	   case 0xe7:
	        key_data = 3;
			break;	
	   case 0xde:
	        key_data = 4;
			break;
	   case 0xdd:
	        key_data = 5;
			break;
	   case 0xdb:
	        key_data = 6;
			break;
	   case 0xd7:
	        key_data = 7;
			break;			
	   case 0xbe:
	        key_data = 8;
			break;
	   case 0xbd:
	        key_data = 9;
			break;
	   case 0xbb:
	        key_data = 10;
			break;
	   case 0xb7:
	        key_data = 11;
			break;	
	   case 0x7e:
	        key_data = 12;
			break;
	   case 0x7d:
	        key_data = 13;
			break;
	   case 0x7b:
	        key_data = 14;
			break;
	   case 0x77:
	        key_data = 15;
			break;	 
	  }

   return key_data;           //傳回按鍵實際對應值
}


void delay(unsigned int t)
{
   unsigned int i;
   while(t--)
     {
      i=10000;
      while(i--);
     }
}