/********基于AT89S52單片機的多功能智能函數信號發生器*******************
*********制作人：04電子信息工程  何貴平********************************
*********完成時間：2007年9月20日*************************************/
#include <reg52.h>
#define uc unsigned char
#define ui unsigned int

sbit P2_3=P2^3;
sbit P2_2=P2^2;
sbit P2_1=P2^1;
sbit P2_0=P2^0;
sbit P3_3=P3^3;

uc code tosin[256]={0x80,0x83,0x86,0x89,0x8d,0x90,0x93,0x96,0x99,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,0xb1,0xb4,0xb7,0xba,0xbc,0xbf,0xc2,0xc5
,0xc7,0xca,0xcc,0xcf,0xd1,0xd4,0xd6,0xd8,0xda,0xdd,0xdf,0xe1,0xe3,0xe5,0xe7,0xe9,0xea,0xec,0xee,0xef,0xf1,0xf2,0xf4,0xf5
,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfd,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfd
,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf4,0xf2,0xf1,0xef,0xee,0xec,0xea,0xe9,0xe7,0xe5,0xe3,0xe1,0xde,0xdd,0xda
,0xd8,0xd6,0xd4,0xd1,0xcf,0xcc,0xca,0xc7,0xc5,0xc2,0xbf,0xbc,0xba,0xb7,0xb4,0xb1,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x99
,0x96,0x93,0x90,0x8d,0x89,0x86,0x83,0x80,0x80,0x7c,0x79,0x76,0x72,0x6f,0x6c,0x69,0x66,0x63,0x60,0x5d,0x5a,0x57,0x55,0x51
,0x4e,0x4c,0x48,0x45,0x43,0x40,0x3d,0x3a,0x38,0x35,0x33,0x30,0x2e,0x2b,0x29,0x27,0x25,0x22,0x20,0x1e,0x1c,0x1a,0x18,0x16
,0x15,0x13,0x11,0x10,0x0e,0x0d,0x0b,0x0a,0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x02,0x02,0x01,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x02 ,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0d,0x0e,0x10,0x11,0x13,0x15
,0x16,0x18,0x1a,0x1c,0x1e,0x20,0x22,0x25,0x27,0x29,0x2b,0x2e,0x30,0x33,0x35,0x38,0x3a,0x3d,0x40,0x43,0x45,0x48,0x4c,0x4e 
,0x51,0x55,0x57,0x5a,0x5d,0x60,0x63,0x66 ,0x69,0x6c,0x6f,0x72,0x76,0x79,0x7c,0x80 };
uc b=0,c=0,d=0,e=0;

void key1(void);
void key2(void);
void key3(void);
void key4(void);
void judge(void);



/************去抖鍵盤動延時************************************/
void delays()
  {
    ui  i;
    for(i=2000;i>0;i--);
         
  }

/*********外部中斷函數**************************/
void into(void) interrupt 0 using 1
{
   judge();
}


/***********3*3鍵盤掃描，從P2.2~P2.7***********/

 void judge(void)
 {  

 while(1)
 {
  uc key=0;
  uc a,k,j=0;
  uc code su[]={0x7f,0xbf,0xdf,0xef};//掃描字
     
          P2=0xf0;  // 11100011
          k=P2&0xf0;                 //抖動判斷
    if(k!=0xf0)                      //不相等說明有鍵按下
          {
              delays();       
              P2=0xf0;              
              k=P2&0xf0;
                   //進一步判斷
		 if(k!=0xf0)          {
                for(j=0,a=0;a<4;a++,j++)
                 
                   {
                    P2=su[j];
                    if(P2_3==0)key=4*a+1;
                    if(P2_2==0)key=4*a+2;
                    if(P2_1==0)key=4*a+3;
                    if(P2_0==0)key=4*a+4;
				    switch(key)
				       {
					    case 1:key1();break;
						case 2:key2();break;
						case 3:key3();break;
						case 4:key4();break;
						default : break;
					   }			 
                    }
              }
        }
   }
}
/******************主函數***********************/
void main(void)
{
EA=1;
EX0=1;
IT0=0;
EX1=1;
IT0=0;
}

/*****************正弦波******************/
void key4()                   
{
    do
      {              
	     P0=tosin[b];             //正弦波
         b++;
         if(b>256)
         b=0;
	  }while(P3_3);
}

/************三角波***********************/
void key2()                 
{
    do
      {              
	     if(c<128)        
           	P0=c;                      
     	 else 
            P0=255-c;         
         c++;
		 if(c>256)
		 c=0;
	   }while(P3_3);
}

/**********方波*************************/
void key3()              
{
    do
        {
	      if(d<=128)         
        	       P0=0x00;                 
          else
	                P0=0xff;                            
	      d++;
		  if(d>256)
		  d=0;
        }while(P3_3);
}
/*************鋸齒波**********************/
void key1()          
{
     do
          {
           P0=e;
           e++;
          }while(P3_3);
}