51微控制器—矩陣鍵盤-程式碼

#include 
#include "../delay/delay.h"
#include "matrix.h"

/*=====================================================
            按鍵掃描函式，返回掃描鍵值
======================================================*/
unsigned char key_scan(void)
{
	unsigned char keyvalue;
    
	KEYPORT = 0xf0;                         //高四位置高，低四位拉低

    if(0xf0 != keyvalue)
	{
	    delay_ms(10);                       //去抖
		if(0xf0 != keyvalue)                //有按鍵按下
		{
		    KEYPORT = 0xfe;	                //檢測第一行		
			if(0xfe != KEYPORT)
			{
			    keyvalue = KEYPORT;
				keyvalue &= 0xf0;           //過濾干擾
				keyvalue += 0x0e;           //過濾干擾		
		        while(0xfe != KEYPORT);
			    delay_ms(10);               //去抖
			    while(0xfe != KEYPORT);
				return keyvalue;
			}

		    KEYPORT = 0xfd;	                //檢測第二行		
			if(0xfd != KEYPORT)
			{
			    keyvalue = KEYPORT;
				keyvalue &= 0xf0;           //過濾干擾
				keyvalue += 0x0d;           //過濾干擾			
		        while(0xfd != KEYPORT);
			    delay_ms(10);               //去抖
			    while(0xfd != KEYPORT);
				return keyvalue;
			}
		    
			KEYPORT = 0xfb;	                //檢測第三行		
			if(0xfb != KEYPORT)
			{
			    keyvalue = KEYPORT;
				keyvalue &= 0xf0;           //過濾干擾
				keyvalue += 0x0b;           //過濾干擾			
		        while(0xfb != KEYPORT);
			    delay_ms(10);               //去抖
			    while(0xfb != KEYPORT);
				return keyvalue;
			}

		    KEYPORT = 0xf7;	                //檢測第四行	
			if(0xf7 != KEYPORT)
			{
			    keyvalue = KEYPORT;
				keyvalue &= 0xf0;           //過濾干擾
				keyvalue += 0x07;           //過濾干擾			
		        while(0xf7 != KEYPORT);
			    delay_ms(10);               //去抖
			    while(0xf7 != KEYPORT);
				return keyvalue;
			}
		}
	}
  
    return 0xff;
}


/*=====================================================
             按鍵值處理函式，返回掃描鍵值
======================================================*/
unsigned char key_pro(void)
{
    unsigned char keynum;

	keynum = key_scan();
	
	/*按下相應的鍵顯示相對應的碼值*/
	switch(keynum)
	{
	    case 0x7e:
		{
		    return 0;    //0
			break;
		}
	    case 0xbe:
		{
		    return 1;    //1
			break;
		}
	    case 0xde:
		{
		    return 2;    //2
			break;
		}
	    case 0xee:
		{
		    return 3;    //3
			break;
		}
	    case 0x7d:
		{
		    return 4;    //4
			break;
		}
	    case 0xbd:
		{
		    return 5;    //5
			break;
		}
	    case 0xdd:
		{
		    return 6;    //6
			break;
		}
	    case 0xed:
		{
		    return 7;    //7
			break;
		}
	    case 0x7b:
		{
		    return 8;    //8
			break;
		}
	    case 0xbb:
		{
		    return 9;    //9
			break;
		}
	    case 0xdb:
		{
		    return 10;   //10
			break;
		}

	    case 0xeb:
		{
		    return 11;   //11
			break;
		}

	    case 0x77:
		{
		    return 12;   //12
			break;
		}

	    case 0xb7:
		{
		    return 13;   //13
			break;
		}
		
		case 0xd7:
		{
		    return 14;   //14
			break;
		}
		
		case 0xe7:
		{
		    return 15;   //15
			break;
		}

        default:
		{
		    return 0xff;
			break;
		}
	}  
}