鍵盤掃描有中斷方式和查詢方式
#i nclude "jn8515def.h"

/******以下是鍵盤排列圖******
                   |       |       |
PC0  ___1|__2|__3|__
                    |      |        |
PC1  ___4|__5|__6|__
                   |       |        |
PC2  ___7|__8|__9|__
                    |       |       |
PC3  ___C|__0|__S|__  
                    |       |       |
                    |       |       |
               PC4 PC5 PC6
*****************************/  
//下沿為有效鍵值          0    1    2    3    4    5    6    7    8    9  s(10)  c0   c1   c4   c7   cs  c
FLASH uchar cKeyTab[]={0x57,0x6e,0x5e,0x3e,0x6d,0x5d,0x3d,0x6b,0x5b,0x3b,0x37,0x47,0x66,0x65,0x63,0x27,0x67};
FLASH uchar cKeyOut[]={0xef,0xdf,0xbf};           //其中一列為0
FLASH uchar cKeyDir[]={0x10,0x20,0x40};  
uchar cMenu=0;

uchar cKeyVal()
{  static uchar cLastKv,cSameKvNum=0;  
   static   bit bKeyPress=0;
   uchar i,j,cKeytmp=0xff;
   for(i=0;i<3;i++)
   {  DDRC&=0x80;
      DDRC|=cKeyDir[i];
      PORTC=cKeyOut[i];  
      #asm("nop")
      #asm("nop")
      cKeytmp=PINC&0x7f;  
      for(j=0;j<16;j++)
      {  if(cKeyTab[j]==cKeytmp)
         {  cWaitTime=10;          //延時(shí)去抖
            goto Next;  
         }
      }
   }
  // do{                           //等待按鍵釋放
   // }while(!bKeyPress);    
   cSameKvNum=0;  
   bKeyPress=0;
   return 0xff;
Next:
//   delay_ms(2);    
   if(bKeyPress) return 0xff;
   if(cKeytmp==cLastKv)                
   {  if(++cSameKvNum>10)
      {  cSameKvNum=0;
         bKeyPress=1;
         return j;
      }
   }
   else
   {  cSameKvNum=0;  
      cLastKv=cKeytmp;
   }
    
   return 0xff;//返回空鍵值    
}