#include<reg51.h>   
#define uchar unsigned char
#define uint unsigned int
int cnt_h,cnt_l;
sbit spk=P2^3;
//sbit led=P2^0;
uchar cnt,i,step,s_bit;
code uint yin[7]={1912,1704,1516,1432,1276,1136,1012};  //1:低八度 3：高八度
//《北京欢迎你》 简谱代码
code uint song[]={123,125,123,122,123,122,223,123,122,116,121,123,122,222,122,121,116,121,122,123,125,122,123,126,125,116,122,121,121
,122,121,116,121,122,123,125,122,123,126,125,125,123,123,122,123,122,121,125,126,222,115,123,123,222,223,
116,123,122,122,221,423,425,131,125,226,226,125,123,123,125,225,123,125,126,131,132,131,125,123,122,125,223,223,123,125,131,125,226,231,132,131,125,123,125,127,226,223,122,123,125,133,232,127,331,999};
void delay(uint a);//
void init();    // 简谱代码解释：每个音及其节拍用一个三位数表示
void main()     //       三位数的百位表示节奏的整数倍
{       //                     十位表示音的高低(1位低音,3为高音)                   
 init();     //                 个位数表示是哪个基本音素
 while(1)
 {
  step=(song[i]/100)*4; //将2变成其他 数可改变节奏的快慢
 // TH1=(65536-65535)/256;
 // TL1=(65536-65535)%256;
  switch((song[i]/10)%10)
  {
   case 1:
   {
    cnt_h=-(yin[song[i]%10-1]*2)/256;
    cnt_l=-(yin[song[i]%10-1]*2)%256;
    break;
   }
   case 2:
   {
    cnt_h=-yin[song[i]%10-1]/256;
    cnt_l=-yin[song[i]%10-1]%256;
    break;
   }
   case 3:
   {
    cnt_h=-(yin[song[i]%10-1]/2)/256;
    cnt_l=-(yin[song[i]%10-1]/2)%256;
    break;
   }
  }
  TH0=cnt_h;
  TL0=cnt_l;
  TR1=1;
  TR0=1;
 next:
  while(cnt!=step)
   goto next;
 // led=~led;
  TR0=0;
  cnt=0;
  TR1=0;
  delay(200);
  i++;
  if(song[i]==999)
  {
   i=0;
   delay(900);
  } 
 }
}
void init()
{
 EA=1;
 ET0=1;
 ET1=1;
 TMOD=0x11;
 i=0;
 cnt=0;
 TR0=0;
 TR1=0 ;
}
void t0(void) interrupt 1
{
 TH0=cnt_h;
 TL0=cnt_l;
 spk=~spk;
}
void t1(void) interrupt 3
{
// TH1=(65536-65535)/256;
// TL1=(65536-65535)%256;
 cnt++;
}
void delay(uint a)
{
 uint q,k;
 for(q=0;q<84;q++)
  for(k=0;k<a;k++);
}