#include<reg51.h>

sbit wr=P3^6;
sbit rd=P3^2;

sbit key0=P1^0;
sbit key1=P1^1;
sbit key2=P1^2;
sbit key3=P1^3;
sbit key4=P1^4;

unsigned char flag;//flag為0、1、2、3、4時分別為正弦波、方波、三角波、梯形波、鋸齒波

unsigned char const code ZXB_code[256]={
0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,
0xa5,0xa8,0xab,0xae,0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,
0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,0xda,0xdc,0xde,0xe0,
0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf4,
0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,
0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf3,0xf2,
0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe3,0xe1,0xde,0xdc,
0xda,0xd8,0xd6,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,
0xbc,0xb9,0xb6,0xb4,0xb1,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,
0x99,0x96,0x92,0x8f,0x8c,0x89,0x86,0x83,0x80,0x7d,0x79,0x76,
0x73,0x70,0x6d,0x6a,0x67,0x64,0x61,0x5e,0x5b,0x58,0x55,0x52,
0x4f,0x4c,0x49,0x46,0x43,0x41,0x3e,0x3b,0x39,0x36,0x33,0x31,
0x2e,0x2c,0x2a,0x27,0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,
0x15,0x14,0x12,0x10,0xf,0xd,0xc,0xb,0x9,0x8,0x7,0x6,0x5,0x4,
0x3,0x3,0x2,0x1,0x1,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,
0x0,0x1,0x1,0x2,0x3,0x3,0x4,0x5,0x6,0x7,0x8,0x9,0xa,0xc,0xd,
0xe,0x10,0x12,0x13,0x15,0x17,0x18,0x1a,0x1c,0x1e,0x20,0x23,
0x25,0x27,0x29,0x2c,0x2e,0x30,0x33,0x35,0x38,0x3b,0x3d,0x40,
0x43,0x46,0x48,0x4b,0x4e,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,
0x66,0x69,0x6c,0x6f,0x73,0x76,0x79,0x7c
};	//用于生成正弦


unsigned char keyscan()	  //鍵盤掃描函數
{
  unsigned char keyscan_num,temp;

  P1=0xff;
  temp=P1;
  if(~(temp&0xff))
  {
    if(key0==0)
	{
	  keyscan_num=1;
	}
	else if(key1==0)
	{
	  keyscan_num=2;
	}
	else if(key2==0)
	{
	  keyscan_num=3;
	}
	else if(key3==0)
	{
	  keyscan_num=4;
	}
	else if(key4==0)
	{
	  keyscan_num=5;
	}
	else
	{
	  keyscan_num=0;
	}

	return keyscan_num;
  }
}

void init_DA0832()//DA芯片準備函數
{
  rd=0;
  wr=0;
}

void ZXB()//正弦波函數
{
  unsigned int i;
  
  do{
    P2=ZXB_code[i];
	i=i+1;
	}while(i<256);
}

void FB()//方波
{ 
  EA=1;
  ET0=1;
  TMOD=1;
  TR0=1;
  TH0=0xff;
  TL0=0x83;
}

void SJB()//三角波
{
  P2=0x00;
  do{
    P2=P2+1;
  }while(P2<0xff);
  P2=0xff;
  do{
    P2=P2-1;
  }while(P2>0x00);
  P2=0x00;
}

void JCB()//鋸齒波
{
  P2=0x00;
  do{
    P2=P2+1;
  }while(P2<=0xff);
}

void TXB()//梯形波
{
  unsigned char i;

  P2=0x00;
  do{
    P2=P2+1;
  }while(P2<0xff);
  P2=0xff;
  for(i=255;i>0;i--)
  {
    P2=0xff;
  }
  do{
    P2=P2-1;
  }while(P2>0x00);
  P2=0x00;
}

void main()
{
  init_DA0832();
  do
    {
      flag=keyscan();
    }while(!flag);//等待按鍵按下
  while(1)
  {
    switch(flag)
    {
      case 1:
	    do{
	      flag=keyscan();
	      ZXB();
	     }while(flag==1);
	    break;
	  case 2:
	    FB();
	    do{
	      flag=keyscan();
		  }while(flag==2);
		  TR0=0;
	    break;
	  case 3:
	    do{
	      flag=keyscan();
	      SJB();
		  }while(flag==3);
	    break;
	  case 4:
	    do{
	      flag=keyscan();
	      TXB();
		  }while(flag==4);
	    break;
	  case 5:
	    do{
	      flag=keyscan();
	      JCB();
		  }while(flag==5);
	    break;
	  default:
	    flag=keyscan();
	    break;
    }	
  }
}

void timer0(void) interrupt 1
{
  P2=~P2;
  TH0=0xff;
  TL0=0x83;
  TR0=1;
}