從零開始學單片機（八）蜂鳴器唱歌

只要給一個0，它就會“叫”。讓它唱歌的原理很簡單，聲音大小是固定的，讓它的頻率變化，就能讓它發出不同的音符。

代碼中在軟件循環延時過程中，依次給它一個固定頻率的方波，讓它唱起來。

//晶振11.0592

#include

sbit speaker=P2^3;

unsigned char byteTH0,byteT0L,duration;

// 小星星句子，三個一組，第一個表示音符，第二個表示音階，第三個表示延時長度(單位約等于0.1s)

code unsigned char music[]={

1,2,2, 1,2,2, 5,2,2, 5,2,2, 6,2,2, 6,2,2, 5,2,4,

4,2,2, 4,2,2, 3,2,2, 3,2,2, 2,2,2, 2,2,2, 1,2,4,

5,2,2, 5,2,2, 4,2,2, 4,2,2, 3,2,2, 3,2,2, 2,2,4,

5,2,2, 5,2,2, 4,2,2, 4,2,2, 3,2,2, 3,2,2, 2,2,4,

1,2,2, 1,2,2, 5,2,2, 5,2,2, 6,2,2, 6,2,2, 5,2,4,

4,2,2, 4,2,2, 3,2,2, 3,2,2, 2,2,2, 2,2,2, 1,2,4 };

//定時器計時初值，高八位，代表不同音符的頻率

code unsigned char FREQH[]={

0xF2,0xF3,0xF5,0xF5,0xF6,0xF7,0xF8,

0xF9,0xF9,0xFA,0xFA,0xFB,0xFB,0xFC,

0xFC,0xFC,0xFD,0xFD,0xFD,0xFD,0xFE,

0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFF,} ;

//定時器計時初值，低八位，代表不同音符的頻率

code unsigned char FREQL[]={

0x42,0xC1,0x17,0xB6,0xD0,0xD1,0xB6,

0x21,0xE1,0x8C,0xD8,0x68,0xE9,0x5B,

0x8F,0xEE,0x44, 0x6B,0xB4,0xF4,0x2D,

0x47,0x77,0xA2,0xB6,0xDA,0xFA,0x16,};

void song();

void delay(unsigned char t);

void main(void)

{

unsigned char index, step;

TMOD=1;

EA=1;

ET0=1;

while(1)

{

step=0;

while(step<126)

{

index = music[step] + 7 * music[step+1] - 1;

byteTH0 = FREQH[index];

byteT0L = FREQL[index];

duration = music[step+2];

step += 3;

song();

}

delay(10);

}

}

void timer0() interrupt 1

{

TR0=0;

speaker=!speaker;

TH0 = byteTH0;

TL0 = byteT0L;

TR0=1;

}

void delay(unsigned char t)

{

unsigned int i;

unsigned char j=80;

for(i=0; i

while(j--);

TR0=0;

}

void song()

{

TH0 = byteTH0;

TL0 = byteT0L;

TR0 = 1;

delay(duration);

}