[求助]改進板子附帶的電子琴程序

這個是電子琴加播放音樂的程序。。。

這個程序在播放音樂的過程中 ，，，如果按其他的鍵  沒反應(yīng)   只能在放完音樂后才能實現(xiàn)彈奏功能，，，，誰能幫我改下使這程序它在播放的過程中按下按鍵時可以能實現(xiàn)彈奏的功能。。。，，最好能再加一首歌曲上去。。。

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
void PlayMusic();
sbit a=P3^2 ;
sbit BEEP = P3^0;

uchar code DSY_Table[]=
{
  0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e,0xBF
};
uint code Tone_Delay_Table[]=
{64021,64103,64260,64400,64524,64580,64684,64777,64820,64898,64968,65030,65058,65110,65157,65178};
  uchar code SONG_TONE[]=
{
  212,212,190,212,159,169,212,212,190,212,142,159,212,212,106,126,129,169,190,119,119,126,159,142,159,0
};
uchar code SONG_LONG[]=
{
  9,3,12,12,12,24,9,3,12,12,12,24,9,3,12,12,12,12,12,9,3,12,12,12,24,0
};

void DelayMS(uint ms)
{
  uchar t;
 while(ms--)
 {
   for(t=0;t<120;t++);
 }
}
uchar KeyNo;


void Keys_Scan()
{
  uchar Tmp,k;
 P1 = 0x0f;
 DelayMS(2);
 Tmp = P1 ^ 0x0f;
 switch(Tmp)
 {
   case 1: k = 0; break;
  case 2: k = 1; break;
  case 4: k = 2; break;
  case 8: k = 3; break;
  default: return;
 }
 P1 = 0xf0;
 DelayMS(2);
 Tmp = (P1 >> 4) ^ 0x0f;
 switch(Tmp)
 {
   case 1: k+= 0; break;
  case 2: k+= 4; break;
  case 4: k+= 8; break;
  case 8: k+= 12;break;
  default: return;
 }
  KeyNo=k;
}

void Play_Tone() interrupt 1
{
  TH0=Tone_Delay_Table[KeyNo]/256;
  TL0=Tone_Delay_Table[KeyNo]%256;
  BEEP=~BEEP;
  }
void main()
{
  P0 = 0xBF;
 TMOD=0x01;
 IE=0x82;
 while(1)
 {
   if(a==0)
    PlayMusic();
  else
  {P1 = 0xf0;
  if(P1 != 0xf0)
  { Keys_Scan();
  
    P0 = DSY_Table[KeyNo];
   TR0=1;}
  else
  {
  TR0=0 ;
  }
  DelayMS(2);
   }
}
}
  void PlayMusic()
{
  uint i =0,j,k;
 while(SONG_LONG!=0||SONG_TONE!=0)
 {
   for(j=0;j<SONG_LONG*20;j++)
  {
    BEEP = ~BEEP;
   for(k=0;k<SONG_TONE/3;k++);
  }
  DelayMS(50);
  i++;
 }
}