#include <reg52.h>

#define KEYPORT P2

sbit beep = P1^7;

#define SEGPORT P0

unsigned char High;
unsigned char Low;
unsigned char code freq[][2]={ 
  0xD8,0xF7,//00440HZ 1   
  0xBD,0xF8,//00494HZ 2  
  0x87,0xF9,//00554HZ 3  
  0xE4,0xF9,//00587HZ 4    
  0x90,0xFA,//00659HZ 5     
  0x29,0xFB,//00740HZ 6     
  0xB1,0xFB,//00831HZ 7      
 

  0xEF,0xFB,//00880HZ `1
};

unsigned char code SONG_TONE[]={212,212,190,212,159,169,212,212,190,212,142,159,
                                                212,212,106,126,159,169,190,119,119,126,159,142,159,0};
unsigned char 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(unsigned int x)
{
        unsigned char t;
        while(x--)for(t=0;t<120;t++);
}
void PlayMusic()
{
        unsigned int i=0,j,k;
        while(SONG_LONG[i]!=0||SONG_TONE[i]!=0)
        {
                for(j=0;j<SONG_LONG[i]*20;j++)
                {
                        beep = ~ beep;
                        for
 
(k=0;k<SONG_TONE[i]/3;k++);
                }
                DelayMS(10);
                i++;
        }
}


void timer0_init(void)
{
    EA = 1;
    TMOD |= 0x01;
    TH0 = 0;
    TL0 = 0;
    ET0 = 1;
    TR0 = 0;
}




void timer0_isr(void) interrupt 1
{
    TH0 = High;
    TL0 = Low;
    beep = ~beep;
}



void main()
{
    unsigned char num = 0;

    timer0_init();

    while(1)
    {
        switch(KEYPORT)
        {
            case 0xfe : num = 1; break;
            case 0xfd : num = 2; break;
            case 0xfb : num = 3; break;
            case 0xf7 : num = 4; break;
            case 0xef : num = 5; break;
            case 0xdf : num = 6; break;
            case 0xbf : num = 7; break;
            case 0x7f : num = 8; break;
            default : num = 0; break;
        }
        if(num)
        {
            High = freq[num - 1][1];
            Low = freq[num - 1][0];
            TR0 = 1;
        }
        else
        {
            TR0 = 0;
        }
        PlayMusic();
    }
}